Very large cups hold endless French water (4)
I believe the answer is:
dead
'very' is the definition.
(I've seen this before)
'large cups hold endless french water' is the wordplay.
'large cups' becomes 'dd' (large cups in a DD-size bra).
'hold' means one lot of letters goes inside another.
'endless' means to remove the last letter.
'french water' becomes 'eau' (I've seen this before).
'eau' with its last letter taken off is 'ea'.
'dd' going around 'ea' is 'DEAD'.
(Other definitions for dead that I've seen before include "Gone to meet one's Maker" , "no longer with us" , "Deceased; numb" , "dull" , "Lifeless" .)