vi to be in want.
2. lack ·interj exclamation of regret or surprise.
3. lack ·noun blame; cause of blame; fault; crime; offense.
4. lack ·vt to blame; to find fault with.
5. lack ·noun deficiency; want; need; destitution; failure; as, a lack of sufficient food.
6. lack ·vt to be without or destitute of; to want; to need.
7. lack ·vi to be wanting; often, impersonally, with of, meaning, to be less than, short, not quite, ·etc.