IPA: /ˈɔːfənɪst/
KK: /ˈɔfənəst/
This word means the most frequent or common occurrence of something.
She visits her grandmother the oftenest of all her relatives.
Oftenest → It is formed from "often" (from Old English *oft*, meaning frequently or many times) and the superlative suffix "-est" (meaning most). The word "oftenest" means most frequently or the highest degree of frequency.
Think of 'often' meaning frequently, and when you add '-est', it indicates the highest degree. So, 'oftenest' means the most frequent occurrence.