Sketch of a tow-headed runner (4)
I believe the answer is:
skit
'sketch' is the definition.
(short comedy performance)
'a tow-headed runner' is the wordplay.
I cannot really understand how this works, but
'runner' could be 'ski' (something which 'runs', ie moves quickly on snow) and 'ski' is located in the answer.
A single letter 't' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'of' is the link.
Can you help me to learn more?
(Other definitions for skit that I've seen before include "A piece of humorous mimicry" , "Short play which makes fun of something" , "Short satirical piece" , "satirical observation" , "Short humorous act" .)