Green’s Dictionary of Slang

rot v.

[rot n.1 /SE rot]

1. [late 19C] to talk nonsense; thus rotting n. and adj. [rot n.1 ].

2. [late 19C–1930s] to spoil, to interfere with, to ruin [i.e. to render SE rotten].

3. [late 19C+] to tease heavily, to abuse, to denigrate; thus rotting n. [rot n.1 ].

4. [1980s] (US campus) to be irritating or unsatisfactory; usu. as that rots.

In phrases

rot about (v.) (also rot along)

[late 19C–1920s] (UK society) to laze around, to idle, to fool around.

rot someone’s socks off (v.)

[1950s+] to defeat comprehensively.

In exclamations