Golf and aquatic sport becoming more popular? (7)
I believe the answer is:
growing
'becoming more popular?' is the definition.
(as in growing popularity)
'golf and aquatic sport' is the wordplay.
'golf' becomes 'g' (phonetic alphabet: alpha, bravo, charlie etc.).
'and' means one lot of letters go next to another.
'aquatic sport' becomes 'rowing' (rowing is an aquatic sport).
'g'+'rowing'='GROWING'
(Other definitions for growing that I've seen before include "On the increase" , "Developing, maturing" , "Increasing in magnitude" , "crescent" , "Increasing in size and changing" .)