1. smooth, slippery [adjective/adverb]

In general, "glad" refers to an object which is not rough. It is often used when warning for slippery roads in wintertime, or to describe objects with a smooth surface.

Examples:
– "Het tijdschrift heeft een glanzende, gladde voorkant."
("The magazine has a shiny, smooth cover.")

– "Puisterige pubers gebruiken clearasil om een gladde huid te krijgen." 
("Teens with pimples use clearasil to get a smooth skin.")

– "Mijn fietsbanden hebben bijna geen profiel meer; ze zijn helemaal glad."
("My bicycle-tyres don’t have any tread left; they’re all bald.")

– "De gladde wegen leidden tot lange files op de snelwegen." 
("The slippery roads resulted in long traffic jams on the highways.")

– "De sneeuw maakte de weg spiegelglad." 
("The snow made the road as slippery as glass.")

Expressions:
– "Iets glad vergeten": to totally forget something.

Example:
– "Het spijt me heel erg, maar ik ben je verjaardag glad vergeten." 
("I’m so sorry, but I totally forgot your birthday.")

Related words:
– Spiegelglad: as slippery as glass [adjective/adverb].

2. slick [adjective/adverb]

"Glad" can also refer to boys or men. If so, it is seldomly used as a compliment. Someone is "glad" when he’s not to be trusted. I suspect the origin of the word has something to do with an apparent correlation between untrustworthy men and the exuberant amounts of hair gel that these men tend to use to create their slick hairdo. Slightly old-fashioned words for such a type of man are "gladjakker" and "gladjanus".

Examples:
– "Ik zou mijn auto niet van die autohandelaar kopen; hij is veel te glad."
("I wouldn’t buy my car from that car dealer; he’s way too slick.")

– "Kijk maar uit voor die gladde jongens met hun gladde praatjes."
("You’d better watch out for those slick guys with their slick stories.")

Related words:
– Gladjanus: slicker [noun] [de gladjanus, de gladjanussen].
– Gladjakker: slicker [noun] [de gladjakker, de gladjakkers].

monkey [noun] [de aap, de apen]

Even though there is not a single "aap" to be found in the Netherlands (other than in zoos obviously), there is a lot of "aap" related vocabulary. I don’t think this DWOTD is complete, so readers are invited to comment 🙂

Note that although there is a distinction between a "monkey" and an "ape", it is common in spoken Dutch to refer to both as "apen". If you want to be specific, say "mensaap" in the case of an "ape".

Examples:
– "Heb jij wel eens een aap in het wild gezien?" 
("Have you ever seen a monkey in the wild?")

– "Aap, noot, mies…" 
("Monkey, nut, mies." First three words of the traditional reading board ("leesplankje") used in the Netherlands end of the 19th century till mid 20th century (is my guess). See the picture above.)

– "Een aap die geen bananen eet." 
("A monkey that does not eat bananas." This is a memory aid to help you tune your (regular 6 string) guitar. Take the first letter of each word: E-A-D-G-B-E.")

– "Madelon is gek op apekoppen." 
("Madelon really likes ‘apekoppen’." Dutch people in general like liquorice ("drop") and many different kinds are for sale, for example ‘apekoppen’ ("monkey heads"). Note that one should write "apenkoppen" according to the most recent spelling rules.)

– "Apen maken handig gebruik van lianen." 
("Monkeys make clever use of lianes.")

Expressions:
– "Daar komt de aap uit de mouw": the truth is revealed, the real intentions become clear, etc.. Literally "there the monkey comes out of the sleeve".
– "Voor aap staan": to be made a fool of, to look a right monkey. When you do this to somebody, the expression becomes "iemand voor aap zetten".
– "In de aap gelogeerd zijn": to be in a fix, to be up the creek (shit creek without a paddle if you so prefer 🙂 ). Allegedly, there once was an inn called "de aap" in Amsterdam, and it was really really bad. (The verb "logeren" means "to stay (at), to spend the night".)
– "Brutale/lelijke aap!": literally ‘cheeky/ugly monkey’, this is used to address (very) insolent children.

Related words:
– Mensaap: ape [noun] [de mensaap, de mensapen].
– Na-apen: to imitate, mimic [verb] [aapte na,nageaapt].

Extra:
There is a zoo in the Netherlands near the town of Apeldoorn that is dedicated to monkeys and apes. It is called the "Apenheul" and is a popular family-with-kids outing.

slow [adjective/adverb]

"Traag" refers to the slowness of events, people, internet and so on. A more often-used synonym of "traag" is "langzaam". The difference between the two words is that people will choose "traag" if they are starting to get a bit annoyed, whereas "langzaam" can also be a good thing.

Examples:
– "Hij loopt zo traag als een slak hoewel er niets mis is met zijn conditie." 
("He walks like a snail although there’s nothing wrong with his fitness.")

– "Ik kom echt traag op gang elke dag, vooral nu het nog steeds donker is als ik opsta ‘s ochtends." 
("I really get off to a slow start every day, especially now it’s still dark when I get up in the morning.")

– "Zij is een beetje traag van begrip vandaag omdat ze maar drie uur heeft geslapen vannacht." 
("She’s a bit slow-witted today since she’s only slept three hours last night.")

– "Internet is zo traag vandaag, is er een technische storing ofzo?" 
("Internet is so slow today, is there a technical malfunction or something?")

– "<Plaatje:> Graag traag (rijden)".
(" ("<Picture:> (Drive) slowly please.")

– "De bestuurder in de auto voor ons rijdt zo traag als een oma." 
("The driver in the car before us drives as slow as a grandma.")

Related words:
– Langzaam: slow [adjective/adverb].
– Snel: fast [adjective/adverb].
– Traagheid: slowness, tardiness [noun] [de traagheid, no plural].