Nips up to engage in making yarn (4)
I believe the answer is:
spin
'engage in making yarn' is the definition.
I can't judge whether this defines the answer.
'nips up' is the wordplay.
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'nips' written backwards gives 'SPIN'.
'to' is the link.
Can you help me to learn more?
(Other definitions for spin that I've seen before include "Toss" , "This doctor is a political story-polisher" , "Snip in order to rotate" , "Turn - type of New Labour doctor" , "Take a turn" .)