suffix
Attaches to a number or amount to mean 'less than that amount'. Often used with counters or quantities.
会議は一時間足らずで終わった。
The meeting ended in less than an hour.
千円足らずの買い物だった。
It was a purchase of under 1,000 yen.
suffix
Attaches to a noun to express that something is lacking or insufficient in that quality. Often used in set phrases like 注意足らず (insufficient attention) or 勉強足らず (insufficient study).
彼の失敗は注意足らずが原因だ。
His failure was due to insufficient attention.
勉強足らずで試験に落ちた。
I failed the exam because of insufficient study.