Meaning

adverb with little or no delay

adverb in a punctual manner

adverb at once (usually modifies an undesirable occurrence)

originEtymology tree English prompt Proto-Indo-European *leyg-der. Proto-Germanic *līkąder. Proto-Germanic *-līkaz Proto-Germanic *-ê Proto-Germanic *-līkê Proto-West Germanic *-līkē Old English -līċe Middle English -ly English -ly English promptly From prompt + -ly.

Etymology from Wiktionary, CC BY-SA 3.0