Become short of time leaving sketch unfinished (4,2)
I believe the answer is:
draw in
'become short of time' is the definition.
I can't judge whether this defines the answer.
'sketch unfinished' is the wordplay.
'sketch' becomes 'drawing' (I've seen this before).
'unfinished' means to remove the last letter.
'drawing' with its last letter removed is 'DRAW IN'.
'leaving' acts as a link.
Can you help me to learn more?
(Other definitions for draw in that I've seen before include "Of time or daylight, become shorter" , "Reduce" , "(Of days) shorten" .)