Something that is insufficient is not large enough in amount or degree for a particular purpose.
sufficient , enough , adequate
He decided there was insufficient evidence to justify criminal proceedings.
他判定没有充分的证据提起刑事诉讼。
These efforts were insufficient to contain the burgeoning crisis.
这些努力不足以控制迅速扩散的危机。
The income was proving insufficient to clear her debts.
她的收入都不足以还清欠款。