- occasional - occurring from time to time; "took an occasional glass of wine"
Antonym: frequent (indirect, via infrequent)
- episodic, occasional - occurring or appearing at usually irregular intervals; "episodic in his affections"; "occasional headaches"
Antonym: predictable (indirect, via unpredictable)
- casual, occasional - employed in a specified capacity from time to time; "casual employment"; "a casual correspondence with a former teacher"; "an occasional worker"
Antonym: regular (indirect, via irregular)