Drink a lot of salt water? (3)
I believe the answer is:
tea
'drink' is the definition.
(tea is a kind of drink)
'a lot of salt water?' is the wordplay.
'a lot of' means to remove the last letter (I've seen 'lots of' mean this (the majority of the word)).
'salt water?' becomes 'tear' (a teardrop contains salt).
'tear' with its last letter taken away is 'TEA'.
(Other definitions for tea that I've seen before include "Lapsang souchong" , "Cha" , "Leaves for brewing" , "Elevenses" , "Sort of garden, chest or service" .)