Six right to leave a sign (5)
I believe the answer is:
virgo
'a sign' is the definition.
(I know that Virgo is a sign)
'six right to leave' is the wordplay.
'six' becomes 'VI' (Roman numerals).
'right' becomes 'r' (common abbreviation).
'to leave' becomes 'go' (to go is to depart or leave).
'vi'+'r'+'go'='VIRGO'
(Other definitions for virgo that I've seen before include "Zodiacal sign" , "Large constellation -- sign of the zodiac" , "A constellation, a cluster" , "Star sign" , "House" .)