Deficiency, absence or dearth

verb

1. To be deficient or missing

   "time is lacking for a full explanation"

2. To be short or have need of something

   "he will not lack for advisers"

3. To stand in need of suffer from the absence or deficiency of

   "lack the necessities of life"

noun

1. The fact or state of being wanting or deficient

   "a lack of evidence"

2. Something that is lacking or is needed

idiom

1. Failure to act

   "The protesters criticized the administration's lack of action on many issues."

idiom

1. Used to say that there is not enough of the thing that has been mentioned

idiom

1. Not having (the thing specified)

   "They called it a comet, for lack of a better term/word."

idiom

1. A lot of much

   "There was no lack of interest in the proposal."

idiom

1. Used to say that someone's lack of success is not due to a failure to try to succeed

idiom

1. To have everything one needs

   "Their children lack/want for nothing."