To lash out is to attack suddenly, with words or with blows. No warning, and usually out of pain.
The physical sense is a sudden strike, and a frightened animal or a cornered person will lash out. The verbal sense is commoner in reporting, and lashing out at critics means attacking them publicly and angrily. It takes at. There is a completely separate British sense meaning to spend extravagantly, so lashing out on a new car is a small boast rather than an act of aggression.
For the verb's chief current sense (to attack suddenly), by surface analysis suggests reaching out with the lash (either literally or figuratively); however, the verb is entered in various early-19th-century dictionaries with various senses, only some of which have to do with attacking, kicking, or similar. One of them corresponds to today's splash out (that is, to break out into spending), while another corresponds to breaking out into expressing oneself verbally.
Etymology from Wiktionary, CC BY-SA
Practised in Phrasal Verbs, A Man Called Ove
First appears in chapter 34 of A Man Called Ove.
Practise this word