Word with jerk or joint (4)
I believe the answer is:
knee
'word with jerk or joint' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for knee that I've seen before include "Lower limb joint" , "This is capped by the patella" , "one is bent on submission" , "Human joint" , "Where the femur meets the tibia" .)