Other forms: slapped, slaps, slapping
To slap someone is to hit them with the flat of an open hand — a wide, loud, stinging blow rather than a punch. A slap across the face at the end of an argument; a slap on the back when your friend finally gets the job.
The noun is the same word: you give someone a slap, and you hear the slap of wet shoes on a tiled floor. Slap also means to put something down hard and carelessly — slap the file on the desk, slap a coat of paint on the fence, slap a fine on a company that deserved it. As an adverb it means squarely: the ball went slap into the window. A slap-up meal is British and means a big, generous one. Keep the neighbours apart: a punch uses a closed fist, a smack is much the same as a slap, and a pat is gentle and friendly.
1verbslapTo hit someone with the flat of an open hand.
“She slapped him hard enough to leave a mark on his cheek.”
2verbputTo put something down quickly, carelessly or with force.
“He slapped the newspaper on the counter and asked for change.”
3nounblowA blow with the flat of the hand, or the sound of one.
“The slap of the waves against the hull kept him awake.”
Too few real examples of this word to estimate which sense is commonest.
slap is a blow with an open hand.
Also accepted in games: smack
Slap comes from Middle English slappen, and there the trail goes cold — the best guess is that the word simply copies the sound. Low German has Slappe for a slap, and German Schlappe, from the same noise, drifted into meaning a defeat. Italian sleppa is another slap. It looks like a word several languages invented separately, because the hand makes that noise everywhere.
Middle English
slappen
English, today
slap
From Middle English slappen, of unknown origin, possibly imitative of the sound. Compare Low German Slappe (“slap”), whence also German Schlappe (“defeat”). Compare also Italian sleppa (“slap”).
Etymology from Wiktionary, CC BY-SA