aff. a suffix forming the superlative degree of adjectives and adverbs:fastest; soonest; warmest[/ex]•Etymology: ME; OE -est, -ost II-estor -staff. an ending of the second person singular indicative of verbs, now occurring only in archaic forms or used in solemn or poetic language:knowest; sayest; goest[/ex]•Etymology: ME; OE -est, -ast, -st, 2nd pers. sing. pres. indic. endings of some verbs (-s earlier v. ending +-t, by assimilation from thū thou I) and 2nd pers. sing. past endings of weak verbs (earlier -es+-t)
From formal English to slang. 2014.