bestie

best (English)

(transitive) To beat in a contest. To surpass in skill or achievement. .. Most; largest. To the most advantage; with the most success, cause, profit, benefit, or propriety. (countable) The person (or persons; or thing or things) that is (are) most excellent.. (uncountable) One's best behavior.. (uncountable) The supreme effort one can make, or has made.

-ie (English)

(occasionally, sometimes, derogatory) Forming nouns signifying the person associated with suffixed noun or verb.. Forming diminutive or affectionate forms of nouns or names.

bestie (English)

(informal) One's best friend.