Phrasal Verb 'Knuckle'

We have 2 phrasal verb definitions related to 'Knuckle'.

Knuckle down

Meaning: Make a great effort

Example: I've got my exams next week and I haven't done much work, so I'd better KNUCKLE DOWN.

Knuckle under

Meaning: Submit to authority

Example: The teacher made the students KNUCKLE UNDER and hand their projects in on time.