Girl friend seen around fourth of August every year (8)
I believe the answer is:
annually
'every year' is the definition.
(synonyms)
'girl friend seen around fourth of august' is the wordplay.
'girl' becomes 'Ann' (woman's name).
'friend' becomes 'ally' (an ally is a friend or supporter).
'seen around' indicates putting letters inside.
'fourth of august' becomes 'u' (4th letter of 'august').
'ann'+'ally'='annally'
'annally' going around 'u' is 'ANNUALLY'.
(Other definitions for annually that I've seen before include "Every year" , "as MOTs must be renewed" , "at regular intervals" , "As Christmas is coming" .)