Lingering means staying on long after the source has gone. Smoke in a curtain, or a doubt that will not settle.
It suits smells, tastes, doubts and looks, and each of those gives a standard phrase: a lingering smell, a lingering doubt, a lingering look. The verb linger means to remain longer than expected, often unwillingly to leave, and lingering over a meal is a pleasure rather than a fault. Medicine uses it grimly, since a lingering illness is a slow one. The related word is long, and the sense of time stretching runs through all of it.
1adjectivelingeringRemaining for a long time after the cause has gone.
“There was a lingering smell of woodsmoke.”
Proto-Germanic
*langijaną
Proto-West Germanic
*langijan
Old English
lenġan — to lengthen, delay, extend
Middle English
lengeren
English
linger
English, today
lingering
Built from
From linger + -ing. linger comes from Middle English lengeren, frequentative of lengen (“to stay, dwell, tarry”), from Old English lenġan (“to lengthen, delay, extend”), from Proto-West Germanic langijan, from Proto-Germanic langijaną (compare West Frisian lingje (“to linger”), Dutch lengen, German längen, Icelandic lengja (“to lengthen”)), related to the root of long. Equivalent to linge or long + -er.
Etymology from Wiktionary, CC BY-SA