A thumb war.

plural of pea-knuckle war

plural of white knuckle ride

plural of white-knuckle ride

(literally) to tap one's knuckles on an object such as a desk or wall to attract attention or as a signal of commmunication. / (somewhat dated, idiomatic) to give someone a punishment.

present participle of knuckle down

present participle of knuckle under

present participle of bare-knuckle

Boxing that is done without boxing gloves. / Ruthless competition.

present participle of bare knuckle