IPA: /əˈseɪl/
KK: /əˈseɪl/
To attack someone or something in a violent or aggressive way, either physically or verbally.
The critics assailed the movie for its poor storyline.
Past: assailed
Past Participle: assailed
Assail is formed from "ad-" (meaning to) and "salire" (meaning to leap or jump). The word originally described the act of leaping upon someone, hence the meaning of attacking or assaulting.
Think of 'leaping' ('salire') onto someone when you 'assail' them — that's why it means to attack.