unceremonious

adjective

1 he waved them to an unceremonious halt:

abrupt, sudden, hasty, hurried, summary, perfunctory, undignified, rude, impolite, uncivil, discourteous, unmannerly, offhand, dismissive;

informal off.

▷antonyms polite.

2 an affable, unceremonious man:

informal, not formal, casual, relaxed;

easy-going, easy, familiar, natural, unreserved, open, free, loose;

informal laid-back, free and easy.

▷antonyms formal.

unceremonious Oxford Dictionary of English