Dissuade bizarre tree with old penny (5)
I believe the answer is:
deter
'dissuade' is the definition.
('deter' can be a synonym of 'dissuade')
'bizarre tree with old penny' is the wordplay.
'bizarre' indicates anagramming the letters.
'with' is an insertion indicator.
'old penny' becomes 'd' (**).
'tree' anagrammed gives 'eter'.
'eter' placed around 'd' is 'DETER'.
(Other definitions for deter that I've seen before include "'Discourage, dissuade (5)'" , "Try to prevent" , "Dishearten" , "Discourage or prevent from doing something" , "Discourage or impede" .)