flare

The verb 'flare' emerged in the mid-16th century, its origins obscure but likely imitative, perhaps meant to evoke the sound or visual effect of a sudden, flickering light or movement, like a flag or flame in the wind. It is possibly related to the Norwegian word 'flara', meaning 'to blaze' or 'to flaunt in gaudy clothes', suggesting a connection to both light and conspicuous display. From its core sense of a sudden, unsteady burst of light, the meaning extended metaphorically to describe anything that erupts or intensifies suddenly, such as emotions, violence, or the widening shape of a skirt or nostrils. This journey from a probable sound/action imitation to a word describing both literal and figurative bursts of energy exemplifies semantic broadening based on perceived resemblance.

The word 'flare' is a simplex word of uncertain, possibly onomatopoeic or imitative origin. It is not productively composed of smaller, recognizable morphemes in modern English.