whiff

The noun is possibly:

waf, waif, waife (“odour, scent”), possibly from waven (“to move to and fro, sway, wave; to stray, wander; to move in a weaving manner; (figuratively) to hesitate, vacillate”), from Old English wafian (“to wave”), ultimately from Proto-Indo-European *webʰ- (“to braid, weave”); or

wef (“a blow, stroke”), from weven (“to travel, wander; to move to and fro, flutter, waver; to blow something away, waft; to cause something to move; to fall; to cut deeply; to sever; to give up, yield; to give deference to; to avoid; to afflict, trouble; to beckon, signal”); further etymology uncertain, perhaps from Old English wefan (“to weave”) (ultimately from Proto-Indo-European *webʰ- (“to braid, weave”)), or from wǣfan (see bewǣfan, ymbwǣfan); and

partly onomatopoeic.

Noun sense 6 (“name of a number of flatfish”) is possibly derived from sense 1 (“brief, gentle breeze; a light gust of air”), sense 4 (“small quantity of cloud, smoke, vapour, etc.”), and other such senses.

The verb and adjective are derived from the noun. Verb sense 2.6 (“to catch fish by dragging a handline near the surface of the water from a moving boat”) is possibly derived from sense 1.1 (“to carry or convey (something) by, or as by, a whiff or puff of air”), sense 2.2 (“to be carried, or move as if carried, by a puff of air”), and other such senses.

The interjection is derived from noun sense 7.4 (“a sound like that of air passing through a small opening; a short or soft whistle”).