expression, i-adjective
have plenty of; not lacking in
Used to express that someone or something has an abundance of a particular quality, resource, or thing. Often appears in the pattern 〜に事欠かない.
彼は話題に事欠かない。
He never runs out of things to talk about.
この地域は水に事欠かない。
This region has plenty of water.
不足しない is a straightforward negation of 'lack', while 事欠かない is a set phrase emphasizing abundance.
From 事 (thing, matter) + 欠く (to lack) in the negative form 欠かない, literally 'not lacking in things'. The exact historical derivation is uncertain.