Not obtained by search or effort. Frequently in loose const.: Without being sought for; without search.

Having no antecedent cause. fortuitous.

Not occasioned, without occasion or cause. Also: unaccustomed.

(un-, prefix1 affix 2.)

(un-, prefix1 affix 2)

Without occasion; not made or intended for a special occasion.

That has no cause; acausal. Cf. aetiological, adj.

Not capable of being caused; having no cause.