Support limit or some extremes (7)
I believe the answer is:
endorse
'support' is the definition.
(endorsing is a kind of supporting)
'limit or some extremes' is the wordplay.
'limit' becomes 'end' (I've seen this before).
'extremes' suggests removing the centre.
'some' with its middle removed is 'se'.
'end'+'or'+'se'='ENDORSE'
(Other definitions for endorse that I've seen before include "Support (with signature)" , "Give one's sanction to" , "Champion" , "Pass" , "Approve or underwrite" .)