Takashi successfully deceived his girlfriend.
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means deceit, so when you're doing deceit, you are going to deceive someone.
As a human everyone would know who you are. You can't deceive anyone like that. But, as a moo (あざむ)... a cow is what I mean... nobody would know who you are.