15 across
Knocked
back
the
drink
(over
a
gallon)
for
some
considerable
time
(4)
Knocked back the drink (over a gallon) for some considerable time (4)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
The definition is for some considerable time, meaning AGES. "The drink" is SEA, which "knocked back" (reversed) gives AES, and G (for gallon) is inserted to produce A-G-ES.