Endorse what those on high table do after dinner? (7)
I believe the answer is:
support
'endorse' is the definition.
(I know that endorse can be written as support)
'those on high table do after dinner?' is the wordplay.
I cannot quite understand how this works, but
'high' could be 'up' (associated in meaning) and 'up' is found within the answer.
The remaining letters 'sport' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'what' acts as a link.
Can you help me to learn more?
(Other definitions for support that I've seen before include "Bolster or back up" , "Prop" , "used to give strength?" , "Help -- encourage" , "Bear; corroborate" .)