Dost

Part of speech: verb

Definitions

1. An archaic form of the verb do used with the pronoun thou to mean you perform or carry out an action
2. The old-fashioned second-person singular present form of the verb do, once used with thou
3. Used in older English with thou, this form of do indicates the person addressed is performing an act

Etymology: "Dost" is the archaic second-person singular form of "do", the one used with "thou" in sentences like "thou dost protest too much." It is simply "do" with the ending "-st" attached, the same ending that appears on other old verb forms like "wilt" and "shalt". The verb "do" traces back through Old English "dōn", from Proto-West Germanic "dōn" and Proto-Germanic "dōnąn", all the way to a Proto-Indo-European root meaning "to put" or "to place". Its older forms carried the "-st" ending as a regular part of the second-person singular conjugation, so "dost" was the everyday form for addressing one person as "thou" for centuries.