Maybe this:
http://www.google.com/search?rlz=1C1GGGE_enUS379US379&sourceid=chrome&ie=UTF-8&q=nolo+contendere
can't think of the word where: someone is actually guilty but their allowed to act like their innocent. like nothing happened
3 answers
put on a poker face?
or perhaps "acting dumb."
Sra
Sra