Gratis fashion at a stroke (9)
I believe the answer is:
freestyle
'a stroke' is the definition.
The definition and answer can be both related to natural events as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'gratis fashion' is the wordplay.
'gratis' becomes 'free' (synonyms).
'fashion' becomes 'style' (synonyms).
'free'+'style'='FREESTYLE'
'at' acts as a link.
Can you help me to learn more?
(Other definitions for freestyle that I've seen before include "any kind you like" , "How one may swim" , "with little regulation" , "Race where swimmers can choose what stroke to use" , "no-holds-barred event" .)