Dash to see groom boarding launch (10)
I believe the answer is:
sprinkling
'dash' is the definition.
(thesaurus)
'groom boarding launch' is the wordplay.
'groom' becomes 'prink' (prink can mean to groom or tidy oneself).
'boarding' is an insertion indicator.
'launch' becomes 'sling' (both can mean to throw).
'prink' placed within 'sling' is 'SPRINKLING'.
'to see' acts as a link.
(Other definitions for sprinkling that I've seen before include "Drizzling" , "trickle" , "Not much water" .)