(of difficulties etc) too large or serious to oppose, deal with, successfully

impossible

(an act of) denying, refusing

contradiction, denial

not at any time; not at any time up to the present; (used for emphasis in place of 'not')

not at any time

never again

not at any time

to take back or withdraw (a statement, offer, opinion etc)

take back; renege on

to clean (the inside of) something

cancel, revoke