IPA: /ˈsɛd.ləm.li/
KK: /ˈsɛldəmli/
Not occurring often; infrequently.
She seldomly goes out to eat at restaurants.
Seldomly → It is formed from "seldom" (from Old English *seldum*, meaning rarely) and the suffix "-ly" (meaning in a manner of). The word "seldomly" means in a manner that is rare or infrequently.
Think of the word 'seldom' meaning rare, and remember that 'seldomly' describes doing something in a rare manner.