Green’s Dictionary of Slang

acting like a fool.

a.1963		‘The Fall’ in D. Wepman et al. Life (1976) 82: They’re just ruining the name of a hell of a game, / ’Cause the pimps are doing the simping.
1973		D. Goines Street Players 15: That’s the difference in pimpin’ and simpin’, man. I let all my ladies go first class, all the time.