Leave a Spanish gentleman outside bar (7)
I believe the answer is:
abandon
'leave' is the definition.
(to abandon is to leave or desert)
'a spanish gentleman outside bar' is the wordplay.
'spanish gentleman' becomes 'don' (formal term of address for a man in Spanish).
'outside' means one lot of letters goes inside another (some letters go outside others).
'bar' becomes 'ban' (bar can mean to ban or prohibit).
'a'+'don'='adon'
'adon' going around 'ban' is 'ABANDON'.
(Other definitions for abandon that I've seen before include "Leave (a place) for ever" , "Evacuate; desert" , "Give up (something) completely" , "Desert, strand" , "Leave, desert" .)