1. tough guy; wild one; fearless fighter; stalwart

2. veteran (in a particular field); expert; old hand

3. person of surprising audacity; someone with a lot of nerve; brazen individual

4. (crime of) pickpocketing (Usually kana, police jargon; oft. written モサ)

5. investigator specialized on pickpocketing; unit specialized on pickpockets (Usually kana, police jargon; oft. written モサ)