Market saturation holds back sensation (5)
I believe the answer is:
taste
'sensation' is the definition.
(I know that taste is a type of sensation)
'market saturation holds back' is the wordplay.
'holds' says the answer is hidden in the clue.
'back' is a reversal indicator.
'etsat' is hidden within 'market saturation'.
'etsat' written backwards gives 'TASTE'.
(Other definitions for taste that I've seen before include "Predilection" , "Brief experience (of something)" , "Preference" , "Dash" , "Appreciation, discernment" .)