check = 確認する／調べる check it out = よく見て!／注目して!／試してみて!...

Well, nowadays Japanese seem to keep taking more and more foreign words in their daily conversations; and for "check", it could also be written in "katakana" (片仮名) as チェック！For instance, (貴方は) このビデオを 要 チェックだ！= You have to check out/take a look on this video! [Well, usually it happens on the advertisements for some videos (include the adult ones :) printed in magazines.]