Explanation
Expresses insufficiency or lack; 'not enough', 'insufficient'.
Formation
Noun + (が) 足りない, Verb-casual + ほど/だけ + (が) 足りない
Detailed explanation
The ～足りない pattern simply means that something is not sufficient in quantity, time, detail, ability, etc. It’s the negative form of 足りる ('to be enough').
Examples
私の日本語の能力はまだまだ足りない。
Watashi no nihongo no nouryoku wa madamada tarinai.
My Japanese skills are still not enough.
時間が足りないから、今すぐ行かなきゃ。
Jikan ga tarinai kara, ima sugu ikanakya.
We don't have enough time, so we must go right now.
彼の説明には詳細が足りない。
Kare no setsumei ni wa shousai ga tarinai.
His explanation lacks detail.
料理するための食材が足りない。
Ryouri suru tame no shokuzai ga tarinai.
There's not enough food to cook with.
Practice
Grammar content sourced from hanabira.org.