12 across
Short
time
before
new
seed
withdraws
(7)
Short time before new seed withdraws (7)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
Withdraws is your definition, as in formally pulling out of a union or alliance. You've got SEC (a "second" cut short, so "short time") followed by an anagram of SEED (that's your "new" signal) giving you EDES, and the whole lot comes together as SEC plus EDES.