Move slowly, or dash without purpose at first (4)
I believe the answer is:
inch
'move slowly' is the definition.
(I've seen this before)
'dash without purpose at first' is the wordplay.
I cannot really see how this works, but
'at' could be 'in' (synonymous in some cases - eg at school, in school) and 'in' is found within the answer.
The remaining letters 'ch' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'or' is the link.
Can you help me to learn more?
(Other definitions for inch that I've seen before include "Imperial unit of length" , "One of a 2 down in a foot" , "Short length" , "She led the Iceni; bade ciao (anag.)" , "Edge along" .)