Deal badly with worker, taken in by awkward smile (9)
I believe the answer is:
mishandle
'deal badly with' is the definition.
(to mishandle something is to deal with it badly)
'worker taken in by awkward smile' is the wordplay.
'worker' becomes 'hand' (hand is a kind of worker).
'taken in by' means one lot of letters goes inside another.
'awkward' indicates an anagram.
'smile' with letters rearranged gives 'misle'.
'hand' inserted inside 'misle' is 'MISHANDLE'.
(Other definitions for mishandle that I've seen before include "Maltreat" , "Badly judge" , "Fumble" , "Wrongly manage" , "Bungle" .)