(1) ven can be used for "be nerdy," but there may be some other apt English translations. It describes someone who is really into something (or a number of things), a true devotee, who partakes in activities associated with whatever he/she is into – doesn't just sit on the sidelines – and does so very seriously (though, with Klingons, pretty much everything is done very seriously by everybody, so this isn't much of a distinction).

It is possible to say venwI' "one who is nerdy" or "nerd."

(2) Another word for "nerd" is qatru'. Though venwI' is fine, qatru' is more common... and nerdier. (qatru' is the word he gave me before he was perplexed by "nerd vs. geek.")

(3) ngom can be used for "be geeky." Like ven, it's used to describe someone who's really into something and knows a lot about it, but doesn't necessarily partake in related activities – certainly not with the thoroughness of a qatru'. (Also, as with ven, there may be some other English glosses besides "be geeky.")

It is possible to say ngomwI' "one who is geeky" or "geek."

(Festival of the spoken Nerd)