1. Not often.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• unfrequenty,
• 7nfrequently,
• ubfrequently,
• umfrequently,
• ujfrequently,
• uhfrequently,
• undrequently,
• uncrequently,
• unvrequently,
• ungrequently,
• untrequently,
• unrrequently,
• unfeequently,
• unfdequently,
• unffequently,
• unfreqently,
• unfrequentyl,
• Unfrequantly,
• Unfrequentily,
• Unfrequentley

The adjective form of "unfrequently" is "infrequent".

The plural form of "unfrequently" is "unfrequents".

The singular form of the word "Unfrequently" is "Unfrequency" However, it is worth noting that "unfrequently" is not commonly used, and the more common form is "infrequently".