occasional in WordNet English dictionary

1. occurring from time to time
   "casual employment"; "a casual correspondence with a former teacher"; "an occasional worker"
   casual  occasional 
   
2. occurring or appearing at usually irregular intervals
   "episodic in his affections"; "occasional headaches"
   episodic  occasional 
   
3. occurring from time to time
   "took an occasional glass of wine"
   occasional 
   
4. recurring or reappearing from time to time
   "periodic feelings of anxiety"
   periodic  occasional