بایستن

Etymology
From, from + , from  + , from  +.

Verb

 * 1)  to be necessary; must, ought

Conjugation
Only the following conjugations now exist:


 * , extremely commonly used as the equivalent to English constructions with "must", "should", "ought to", "have to", etc.
 * , synonymous to but less common
 * , usually largely synonymous to despite the use of the past stem, but less common and somewhat more polite; more pedantic usage may have this mean "should have", "must have", etc., preserving the past tense
 * , synonymous to
 * and, both rather archaic and used to express any past necessity without regard for grammatical person