Word / formMeaning / explanation
بِعْتُI sold; first-person singular perfect.
بِعْنَthey (women) sold; third-person feminine plural perfect.
بِعْsell; second-person masculine singular imperative.
لَا تَبِعْdo not sell; a jussive prohibition.
All belong to root ب ي ع. Subject endings and jussive morphology account for the contexts in which the weak radical disappears. Correct interpretation depends on the entire form and the attached suffix, not just the first two letters.