Other forms: flushing, flushed, flushes
Flush means perfectly level with the surrounding surface. Flush with the wall, sand it flush, a flush fitting.
It is a builder's and joiner's word and describes an edge that stands neither proud nor recessed. Elsewhere, to flush is to clean something with a rush of water — flush the toilet, flush the system — and a flush is the red rising in a face: a flush of embarrassment. Flush with money means having plenty of it. In cards, a flush is a hand all of one suit. Note flush out, meaning to drive something into the open.
1adjectiveflushPerfectly level with the surrounding surface.
“The new panel sits flush with the old one.”
2verbcleanTo clean something with a rush of water.
“The whole system is flushed once a year.”
3nounrednessA redness rising in the face.
“There was a flush along her cheekbones and nothing said.”
Too few real examples of this word to estimate which sense is commonest.
flush is a level position, or a rush.
Middle English flusshen probably imitates the sound of a sudden rush of water. The level sense came from the idea of a surface brimming exactly to its edge — as water sits flush with the rim of a full glass.
Middle English
flusshen
English, today
flush
From Middle English flusshen, fluschen, of unknown origin. Compare dialectal flusk (“to fly at, startle a bird out of the bush”) and flusker (“to flutter, fly irregularly”). Perhaps related to Middle English flasshen, flasschen, flaschen, see flash; or a Middle English flowen and guschen. Compare stq flutskje, German Low German flutschen, German flutschen.
Etymology from Wiktionary, CC BY-SA