Shortly

INASEC

This abbreviation means "in a very brief period of time."

The clue "Shortly" hints at a word meaning "in a brief time," but the answer "INASEC" is a playful twist. It combines "IN A SEC," a casual way to say "in a second," which fits the idea of something happening shortly. The wordplay relies on abbreviating "second" to "sec" and merging it into a single word.