Unrestrained insect on slope (7)
I believe the answer is:
rampant
'unrestrained' is the definition.
(I've seen this before)
'insect on slope' is the wordplay.
'insect' becomes 'ant' (ant is a kind of insect).
'on' says to put letters next to each other.
'slope' becomes 'ramp' (I've seen this before).
'ant' put after 'ramp' is 'RAMPANT'.
(Other definitions for rampant that I've seen before include "Flourishing excessively as disease may be" , "Out of control" , "Growing or spreading uncontrollably" , "Unrestrained, flourishing excessively" , "Rife" .)