Unpredictable man holding rodent (7)
I believe the answer is:
erratic
'unpredictable' is the definition.
(synonyms)
'man holding rodent' is the wordplay.
'man' becomes 'eric' (I've seen this before).
'holding' means one lot of letters goes inside another.
'rodent' becomes 'rat' (rat is a kind of rodent).
'eric' going around 'rat' is 'ERRATIC'.
(Other definitions for erratic that I've seen before include "Rambling" , "Hit-or-miss" , "Irregular in pattern or movement" , "hit-and-miss" , "Deep affection" .)