Happy, good fellow (4)

I believe the answer is:

glad

'happy' is the definition.
(I know that happy can be written as glad)

'good fellow' is the wordplay.
'good' becomes 'g' (abbreviation).
'fellow' becomes 'lad' (synonyms).
'g'+'lad'='GLAD'

(Other definitions for glad that I've seen before include "These rags are dressy clothes - happy?" , "Made up" , "Not sorry" , "Joyful" , "Contented" .)

I've seen this clue in the Evening Standard.

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