The noun lack has 1 sense (first 1 from tagged texts)
1. (42) lack, deficiency, want -- (the state of needing something that is absent or unavailable; "there is a serious lack of insight into the problem"; "water is the critical deficiency in desert regions"; "for want of a nail the shoe was lost")
Overview of verb lack
The verb lack has 1 sense (first 1 from tagged texts)
1. (31) miss, lack -- (be without; "This soup lacks salt"; "There is something missing in my jewellery box!")