Stand on both sides (8)
I believe the answer is:
straddle
'stand on both sides' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'stand on both' is the wordplay.
'stand' becomes 'staddle' (staddle is a kind of stand).
'on' is an insertion indicator (as in clothing 'on' a person).
'both' becomes 'r' (I am not sure about this - if you are sure you should believe this answer much more).
'staddle' going around 'r' is 'STRADDLE'.
Can you help me to learn more?
(Other definitions for straddle that I've seen before include "Sit with legs apart" , "Go across" , "Sit across" , "Extend over a certain area" , "Bestride" .)