incidental [ɪnsɪˈdɛ.ɾ̃əl]adjective 4noun 2forms 3 adjective4 •Loosely associated; of limited relevance except indirectly; only accidentally related.That character, though colorful, is incidental to the overall plot. •Existing tangentially, being a byproduct, a tangent, or a likely consequence.Injuries are incidental to contact sports: they're going to happen. •Occurring by chance. •Entering or approaching, prior to reflection (more frequently incident). noun2 •Minor items, not further defined. Incidental expense.She's costing us a lot in incidentals. •Something that is incidental. formsincidentals · more incidental · most incidental