(1) When studying math and English, one gets a pretty good idea of what "random" means. So "random acts of violence" (or kindness, no less dangerous according to Wodehouse), or even "let's go do something random and enjoy ourselves" sound normal
(2) But then there is another pattern. Someone comes to a group of young men and says something awkward, sounding more geeky than he'd probably wished. After the man leaves, everyone guffaws (or sniggers as the case may be): "man, that was random" or "he was so random", almost as a synonym to "weird".
Dictionaries are not of much help here, nor my copy of a small corpus of English - so I have to ask the question here:
-- how would you define the meaning of "random" in the second example?
-- Is it new?
-- is it an Americanism?
-- and/or what age groups are more likely to say sth like (2)?
.. or am I getting it wrong and the second use of "random" is absolutely standard and indistinguishable from (1) in the mind of a native speaker?