Green’s Dictionary of Slang

sluff v.

also sluff it all, sluff off
[phonetic sp. of SE slough (off)]

(US) to avoid or shirk one’s responsibilities or work.

[US]Davenport Democrat and Leader (IA) 28 May 32/2–3: Then I jazzed a whirl with a cake-eater on parole but sluffed him for a fluky corn-shredder with a flat tire.
[US] ‘Gila Monster Route’, in N. Anderson Hobo 195: [They] deprived themselves of their daily bread, / And sluffed the coin for dago-red.
[US] (ref. to 1868) N. Kimball Amer. Madam (1981) 56: Charlie had enjoyed a lot of girls during the war, and whisky and looting, sluffing off duty.
[US]Kerouac letter 22 May in Charters I (1995) 315: I know your life in many respects better than Allen does ... not sluffing Allen.
[US]L.P. Boone ‘Gator Sl.’ AS XXXIV:2 156: Those who don’t study, goof off, sluff it all, or pit finals.

In compounds

sluff course (n.)

(US campus) a course that requires little work, a course for which one does little work.

[US]Current Sl. III–IV (Cumulation Issue).