Given support about employee that is dubious (10)
I believe the answer is:
backhanded
'is dubious' is the definition.
(as in a backhanded compliment)
'given support about employee' is the wordplay.
'given' means one lot of letters go next to another.
'support' becomes 'back' (to back is to support or endorse).
'about employee' becomes 'handed' (I can't explain this - if you can you should believe this answer much more).
'back' put next to 'handed' is 'BACKHANDED'.
'that' acts as a link.
Can you help me to learn more?
(Other definitions for backhanded that I've seen before include "not straight" , "Ambiguously flattering remark" , "Some tennis shots are" .)