[Speak] 罪犯用的化名、一時興起

Quotes from Gotham Season 1 Episode 12 & 13

1. 罪犯用的假名、化名: alias

We can't find any records on Gruber prior to his incarceration (監禁、入獄), so we are guessing Gruber is an alias.

2. 一時興起、突然想到: on a whim

Gordon: Is that why you are here?

Lee: I don't know why I am here. Sorry. A whim.

3. 把柄、有用的消息(做為發揮影響力的籌碼): leverage

Give me some leverage. Give me some angle (to solve this case.)