Little woman with small bottle becoming merry (6)
I believe the answer is:
jovial
'merry' is the definition.
(I know that merry can be written as jovial)
'little woman with small bottle' is the wordplay.
'little woman' becomes 'Jo' (character from Little Women).
'with' says to put letters next to each other.
'small bottle' becomes 'vial' (I've seen this before).
'jo'+'vial'='JOVIAL'
'becoming' acts as a link.
(Other definitions for jovial that I've seen before include "Good-humoured, cheerful" , "Cheerful, lively" , "Happy and cheerful" , "Jolly, good-humoured" , "Hearty and cheerful like Jupiter" .)