Drink that's small within reach (6)
I believe the answer is:
shandy
'drink' is the definition.
(I know that shandy is a type of drink)
'small within reach' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'within reach' becomes 'handy' (I've seen this in another clue).
's'+'handy'='SHANDY'
'that's' acts as a link.
(Other definitions for shandy that I've seen before include "Beer/lemonade mixture" , "Beer and lemonade mixture" , "Weakly-alcoholic drink" , "Drink of ale and lemonade 96)" , "Beer-lemonade mix" .)