"be wanting or deficient" (intransitive), late 12c., perhaps from Middle Dutch laken "to be wanting," from lak (n.) "deficiency, fault," or an unrecorded native cognate word (see lack (n.)). Transitive sense "be in want of" is from early 13c. Related: Lacked; lacking.

To lack is primarily and generally to be without, that which is lacked being generally some one thing, and a thing which is desirable, although generally not necessary or very important. [Century Dictionary]