tactless

[takt-lis]

adjective

lacking tact; showing no tact; undiplomatic; offendingly blunt: a tactless remark.

Origin of tactless

First recorded in 1840–50; tact + -less

Related formstact·less·ly, adverbtact·less·ness, noun

rude, inconsiderate, thoughtless, brash, boorish.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Unbelievable and extraordinary display of tactlessness...but should we be surprised?
Diana Movie Ad Posted At Entrance to Pont d'Alma Tunnel Where She Died
Tom Sykes
September 30, 2013

Mrs. Brereton wondered in her own mind where Maud could have got her tactlessness from.
Scarlet and Hyssop
E. F. Benson
And, as the just reply to tactlessness is truth, also tactless, he let Evelyn have it.
The Angel of Pain
E. F. Benson
But they were used to tactlessness from Willie, and they merely winked mutually.
What Will People Say?
Rupert Hughes
It was evident that such a state of affairs portended something more serious than tactlessness or mismanagement.
Wounded and a Prisoner of War
Malcolm V. (Malcolm Vivian) Hay
His isolating and aggressive pride engendered a tactlessness which often spoilt any chances of advancement that came his way.
Souvenir of the George Borrow Celebration
James Hooper

1847, from tact + -less. Related: Tactlessly; tactlessness.