want (v.)

has three main meaning clusters:

 "to wish or desire," as in Do you want a second helping? (see DESIRE); "to lack," as in This deck of cards wants a nine of clubs; and "ought (to)" or "should," as in You want to be careful on icy steps. The first two uses are unquestionably Standard; the "ought (to)" meaning is usually limited to conversation and the Informal and Semiformal writing that imitates it.

 

Kenneth G. Wilson (1923-). The Columbia Guide to Standard American English. 1993.