{v. phr.} To be brave; be determined; face trouble with courage. * /He didn't think that he would ever get out of the jungle alive, but he kept his chin up./ Compare: KEEP A STIFF UPPER LIP.
KEEP ONE'S CHIN UP
Meaning of KEEP ONE'S CHIN UP in English
Slang English vocab. Английский сленговый словарь. 2012