occasionally
adverb
əˈkeɪʒnəli 
əˈkeɪʒnəli sometimes but not often
We occasionally meet for a drink after work.This type of allergy can very occasionally be fatal.Only occasionally was there any doubt that they would succeed.
Definition of occasionally adverb from the Oxford Advanced Learner's Dictionary
əˈkeɪʒnəli əˈkeɪʒnəli 