occasional
1. [ adjective ] occurring from time to time
Examples:

"took an occasional glass of wine"

Related terms: infrequent
2. [ adjective ] occurring or appearing at usually irregular intervals
Synonyms: episodic
Examples:

"episodic in his affections" "occasional headaches"

Related terms: unpredictable
3. [ adjective ] employed in a specified capacity from time to time
Synonyms: casual
Examples:

"casual employment" "a casual correspondence with a former teacher" "an occasional worker"

Related terms: irregular
Similar spelling:   occasionally
  occasion
  occasions