Meaning of occasional

oc•ca•sion•al

1. occurring or appearing at irregular or infrequent intervals; occurring now and then: an occasional headache.
2. intended for supplementary use when needed: an occasional chair.
3. pertaining to, arising out of, or intended for the occasion: occasional verses.
4. acting or serving for the occasion or only on particular occasions.
5. serving as the occasion or incidental cause.