Let everybody down, having no limits (5)
I believe the answer is:
allow
'let' is the definition.
(I know that let can be written as allow)
'everybody down having no limits' is the wordplay.
'everybody' becomes 'all' (all people).
'having no limits' means to look at the middle letters (the edge letters or limits are removed).
The centre of 'down' is 'ow'.
'all'+'ow'='ALLOW'
(Other definitions for allow that I've seen before include "Acknowledge - concede" , "brook" , "Permit, let happen" , "Permit, consent to" , "Permit or acknowledge" .)