CAUSELESS
causeless, fortuitous, uncaused
(adjective) having no cause or apparent cause; “a causeless miracle”; “fortuitous encounters--strange accidents of fortune”; “we cannot regard artistic invention as...uncaused and unrelated to the times”
causeless, reasonless
(adjective) having no justifying cause or reason; “a senseless, causeless murder”; “a causeless war that never had an aim”; “an apparently arbitrary and reasonless change”
Source: WordNet® 3.1
Etymology
Adjective
causeless (comparative more causeless, superlative most causeless)
Having no obvious cause; fortuitous or inexplicable
groundless or unreasonable
Synonyms
• (having no obvious cause): by accident, incidental, random; see also accidental
Anagrams
• sauceless
Source: Wiktionary
Cause"less, a.
Definition: 1. Self-originating; uncreated.
2. Without just or sufficient reason; groundless.
My fears are causeless and ungrounded. Denham.
Cause"less, adv.
Definition: Without cause or reason.
Source: Webster’s Unabridged Dictionary 1913 Edition