Infrequent

• (a.) Seldom happening or occurring; rare; uncommon; unusual.
Found on http://thinkexist.com/dictionary/meaning/infrequent/

infrequent

adjective not frequent; not occurring regularly or at short intervals; `infrequent outbursts of temper`
Found on https://www.encyclo.co.uk/local/20974

Infrequent

In¬∑fre'quent adjective [ Latin infrequens : confer French infrequent . See In- not, and Frequent .] Seldom happening or occurring; rare; uncommon; unusual. « The act whereof is at this day infrequent or out of use among all sorts of men.» Sir T. Ely...
Found on http://www.encyclo.co.uk/webster/I/57

infrequent

not occurring regularly or at short intervals
Found on https://www.vocabulary.com/lists/249614

infrequent

[adj] - not frequent
Found on http://www.webdictionary.co.uk/definition.php?query=infrequent
No exact match found