adverb, adverb taking the 'to' particle
bluntly; harshly; without reserve
Mimetic adverb describing speaking in a blunt, direct, and often harsh manner, stronger than ズケズケ. Dated but still understood.
See also: ズケズケ
彼は上司につけつけと文句を言った。
He bluntly complained to his boss.
つけつけものを言う人だ
He's the type who speaks harshly.