Describes claims, stories, or ideas that lack any basis in fact or reason. Often used in formal or critical contexts. Frequently appears in the compound 荒唐無稽 (こうとうむけい, 'preposterous, absurd').
See also: 荒唐無稽
That rumor is completely unfounded.
His claim was groundless, and no one believed it.
absurd; nonsensical; preposterous
From Chinese 無稽 (wújī), meaning 'without basis' or 'unfounded'. The kanji 無 means 'without' and 稽 means 'to examine' or 'to check', so the literal sense is 'unexamined' or 'unverifiable'.