Deny crowd on Tyneside? (6)
I believe the answer is:
negate
'deny' is the definition.
(I've seen this in other clues)
'crowd on tyneside?' is the wordplay.
'crowd' becomes 'gate' (gate can refer to the crowd for a sporting event).
'on' means one lot of letters go next to another.
'tyneside?' becomes 'NE' (region in North East of England).
'gate' put after 'ne' is 'NEGATE'.
(Other definitions for negate that I've seen before include "Countermand" , "Age ten (anag)" , "Render null or disprove" , "Render ineffective" , "Discredit" .)