Immature wood cut for infusion (5,3)
I believe the answer is:
green tea
'infusion' is the definition.
(I've seen this before)
'immature wood cut' is the wordplay.
'immature' becomes 'green' (synonyms).
'wood' becomes 'teak' (type of timber).
'cut' means to remove the last letter.
'teak' with its final letter taken away is 'tea'.
'green'+'tea'='GREEN TEA'
'for' acts as a link.
(Other definitions for green tea that I've seen before include "Oriental leaves" , "Hot drink - teenager (anag)" , "Infusion" , "Drink - generate (anag)" , "'Asian herbal drink (5,3)'" .)