Green’s Dictionary of Slang

pick n.2

[SE colloq. pick on, to criticize]

1. (Anglo-Irish) a quick-tempered person.

[UK]Partridge DSUE (1984) 876: [...] C.20.

2. (US Und.) a girlfriend.

[US]A.H. Lewis ‘Arabella Weld’ in Sandburrs 167: What for be youse jimmin’ ’round me pick?