brickbat

Short definition from Wiktionary

Noun

1. 1
   A piece of brick, rock, etc., especially when used as a weapon (for example, thrown or placed in a sock or other receptacle and used as a club).
2. 2
   A piece of (sharp) criticism or a (highly) uncomplimentary remark.

Verb

1. 1
   To attack (someone or something) by swinging or throwing brickbats (noun sense 1).
2. 2
   To assail (someone or something) with (sharp) criticism.