1. [late 18C+] (also downish) aware, conscious of, knowledgeable; thus be down upon, to be aware, to be knowledgeable; in 1940s+ use, to be part of the current (youth) fads and fashions.
2. [mid-18C] suspicious.
3. [mid-19C+] first-rate, excellent.
4. [1940s+] (US black) alert, keen to get on, tough, challenging in a fight.
5. [1950s+] willing (to do something), enthusiastic.
6. [1950s+] (US black) fashionably dressed, chic.
7. [1960s] (US black) interesting, current.
8. [1960s+] (US) happening, going on.
9. [1970s+] worked out in a satisfactory manner, under control, going well.
10. [1990s+] (US) in a relationship.
11. [2000s] (US black) feeling well, happy, at one with the world.
see sense 1 above.
[1980s+] (US black) a general term of approval.
[1980s] (US) to attack verbally, to slander.
[1980s+] (US black/campus) used when referring to a situation one does not particularly like, e.g. I ain’t down with this idea!
[early–mid-19C] very well aware.
1. expert, professional (within one’s occupation).
2. describing a wholly admirable person, object or idea.
[1950s+] (US black) loyal to, committed to, in favour of.
[1950s+] (orig. US black) able to look after oneself.
[1970s] (US black) fully aware, completely knowledgeable.
1. [18C–19C] attacking physically.
2. [mid-19C+] annoyed with, disappointed in, holding a negative opinion of.
[late 18C+] aware, knowledgeable.
1. [1930s–40s] through with.
2. [1940s+] involved with, agreeable to.
3. [1940s+] empathetic, emotionally responsive; enjoying, appreciating.
4. [1990s+] (US) friendly with.
[late 19C+] to be aware of the situation, to know what is going on.
[early 19C; 1970s] (UK/US Und., to convey information to someone, to explain, to make someone aware; thus UK Und.) put a swell down, to alert one’s target (typically the target of a pickpocket) that one is about to rob them.