What does couldst mean?
"Couldst" is the archaic second-person singular past tense of the verb "can," meaning "were able to." It was used exclusively with the pronoun "thou" during the Early Modern English period, appearing throughout Shakespeare's plays and the King James Bible: "Thou couldst not have known." Like other second-person singular forms of its era (such as "didst," "hadst," and "wilt"), it took the ending -st or -est to agree with its subject. When English abandoned "thou" in everyday speech in favor of "you," forms like "couldst" fell out of use entirely, replaced by the invariant modern form "could." Today the word survives mainly in historical texts, religious language, poetry, and affectionate or comic imitations of old-fashioned speech. Encountering it signals that a text predates roughly the eighteenth century — or that its author is deliberately reaching for an antique flavor.
verb"Couldst" is the archaic second-person singular past tense of "can," meaning "were able to." It is used only with the pronoun "thou" in Early Modern English, as in Shakespearean and King James Bible usage.
- Archaic second-person singular past tense of "can": were able to; had the ability or possibility to.
"Thou couldst have told me sooner."
"Why couldst thou not keep thy promise?"
"Thou couldst have chosen any path, yet thou chose this one."
Drop a single letter from Shakespeare's vocabulary and you get "couldst" — the verb form that only exists because English once treated "thou" as grammatically special.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of couldst
"Couldst" derives from "could," the past tense of Old English "cunnan" ("to know, know how to"), plus the second-person singular ending -st. The odd "l" in "could" itself arose in Middle English by analogy with "would" and "should," though "could" was originally spelled "coude" without one. Cognates of the root include "cunning," "ken," and "can," all descending from the same Germanic verb of knowing.
Related word forms
How couldst is actually used
"Couldst" belongs exclusively to archaic or deliberately antiquated register. It appears in Early Modern English literature, most famously Shakespeare and the King James Bible, and survives today only in parody, poetry, religious pastiche, or playful imitation. Modern English uses "could" for all persons.
Easily confused with couldst
"Could" is the modern form used with all persons except the archaic second-person singular, which takes "couldst" with "thou."
"Canst" is the archaic second-person singular present tense of "can," while "couldst" is its past tense.