occasional

Occurring, encountered, done, or taken from time to time; irregular or infrequent. synonym: periodic.

Created for a special occasion.

Intended for use as the occasion requires.

Being a factor that makes something possible; being a cause of something.

Acting in a specified capacity from time to time.

Of occasion; incidental; hence, occurring from time to time, but without regularity or system; made, happening, or recurring as opportunity requires or admits: as, an occasional smile; an occasional fit of coughing.

Called forth, produced, or used on some special occasion or event; suited for a particular occasion: as, an occasional discourse.

That serves as or constitutes the occasion or indirect cause; causal.

A production caused by or adapted to some special occurrence, or the circumstances of the moment; an extemporaneous composition.

Occuring at times, but not constant, regular, or systematic; made or happening as opportunity requires or admits; casual; incidental.