An adverb meaning 'at any moment' or 'about to' — indicating that something is likely to happen immediately.
空が暗くなって、今にも雨が降りそうだ。
The sky is getting dark; it looks like it could rain at any moment.
彼は今にも泣き出しそうな顔をしていた。
He looked like he was about to burst into tears at any moment.
今にも出発しそうだから、荷物を持って来てください。
We're about to leave any moment, so please bring your luggage.