Green’s Dictionary of Slang

1. (US campus) ostentatious.

1848		N. Ames Childe Harvard 58: They are long / And rather ‘squirty’ at times.
1856		B.H. Hall College Words (rev. edn) 444: squirty. Showy; fond of display; gaudy.

2. insignificant, jumped-up.

1939

in A. Banks First-Person America (1980) 55: My brother was damned if he was going to report to a squirty watchman.