occasional (adj.)

• accessory
• accidental
• accompanying
• additional
• ado
• adventitious
• afloat
• afoot
• aleatory
• auxiliary
• casual
• causal
• causative
• ceremonial
• circumstantial
• conditional
• constitutive
• contingent
• current
• decisive
• determinative
• effectual
• etiological
• extra
• few
• formative
• incidental
• inessential
• infrequent
• intermittent
• irregular
• nonessential
• occurring
• odd
• off
• on
• ongoing
• originative
• out-of-the-way
• parenthetical
• part-time
• particular
• passing
• periodic
• pivotal
• prevailing
• prevalent
• provisional
• random
• rare
• resultant
• ritual
• scarce
• side
• spare
• special
• sporadic
• supplementary
• uncommon
• unessential