SE in slang uses
[late 19C–1910s] (Irish) one who hangs around at mealtimes in the hope of being offered a meal.
[1970s+] a male homosexual voyeur.
[late 19C+] to look out, to be careful; esp. in imper. watch it! used as a warning or a threat.
to take care, to take note, to be warned; usu. as watch your ass.
[1950s+] to take care of oneself.
[1950s+] to take care; esp. as an imper. when the implication is of a threat from the speaker.
[1950s+] to mind one’s manners, to talk politely; also as imper.
1. to look after or protect someone else.
2. to take care of someone else.
[18C–early 19C] to keep a close watch on someone’s actions.
[1970s+] to be excessively drunk.
[1960s+] (US) to indulge in sexual by-play; thus submarine watching n.
[1910s+] (US) see me go!
[1950s+] (W.I.) watch your manners!