doink, n. — Green’s Dictionary of Slang

doink n.

[echoic of their solidity/dullness]

(US campus)

1. a clumsy, inept person.

1967–8		Baker et al. CUSS 106: Doink. A person who always does the wrong thing.
2000		Freeskiers 🌐 Just a few days ago I actually put on all my ski gear...hahahha...I felt like such a doink with all my ski gear on in the middle of JULY!
1994		A. Duff State Ward 35: What are ya – a doink?

2. an overly hard worker, a ‘grind’.

1968		Current Sl. II:3 16: Doink, n. A bookworm; a grind.
1969		Current Sl. I & II 28: Doink, n. A bookworm, a grind.