also: ぼろくそ
na-adjective, noun
Strongly negative colloquial evaluation; often used with 言う to mean 'to badmouth' or 'to tear to pieces'. The literal components mean 'rags and shit', giving it a vulgar, emphatic tone.
あの映画はボロクソに言われてるね。
That movie is being trashed, isn't it?
上司
My boss tore my proposal to shreds.
na-adjective, noun
disparaging; demeaning; insulting
Describes speech or attitude that is harshly critical and belittling. Often used adverbially as ボロクソに to modify verbs like 言う, 書く, 批判する.
ネットでボロクソに書かれて落ち込んだ。
I got depressed after being slammed online.
An adjective meaning 'shabby' or 'worn-out'; ボロクソ is much stronger and more vulgar, focusing on worthlessness or verbal abuse.
Most common spelling; the word is usually written in kana, and katakana is typical for this emphatic colloquial expression.
Hiragana spelling, also common.
Rarely used kanji form; the kanji 襤褸 (boro) means 'rags' and 糞 (kuso) means 'excrement', but this spelling is almost never seen in modern writing.
Compound of ぼろ (boro, 'rags, tatters') and くそ (kuso, 'shit, excrement'). The combination intensifies the sense of worthlessness or contempt. The exact origin is uncertain, but it likely arose as a vulgar colloquialism.