I'le have thee to him, Thou hast a fine wit, fine fool, and canst play rarely.
How canst thou, then, know their nature, or what is and what only seems to be?
canst thou dash the cup of Freedom from thy lips and bear to drink the bitter draught of slaves?
canst thou not go in with the eunuch, Harmachis, and bring the treasure forth?
Thou art a woman and wise, and canst see in this I lie not—my soul consumes me!
canst thou, husband of my heart's choice, devise some means of escape?
Vergieb soviel du kannst, und gieb soviel du hast—Forgive as much as thou canst, and give as much as thou hast.
canst thou be true to her, forsaking all, follow where her great spirit leads?
If thou must needs lie, which I think is thy nature, canst thou invent no falsehood that may at least do thee some credit?
canst tell me what knights they be who come along so proudly?'
Old English 1st & 3rd person singular present indicative of cunnan "know, have power to, be able," (also "to have carnal knowledge"), from Proto-Germanic *kunnan "to be mentally able, to have learned" (cf. Old Norse kenna "to know, make known," Old Frisian kanna "to recognize, admit," German kennen "to know," Gothic kannjan "to make known"), from PIE root *gno- (see know).
Absorbing the third sense of "to know," that of "to know how to do something" (in addition to "to know as a fact" and "to be acquainted with" something or someone). An Old English preterite-present verb, its original past participle, couth, survived only in its negation (see uncouth), but cf. could. The present participle has spun off as cunning.
Old English canne "a cup, container," from Proto-Germanic *kanna (cf. Old Saxon, Old Norse, Swedish kanna, Middle Dutch kanne, Dutch kan, Old High German channa, German Kanne). Probably an early borrowing from Late Latin canna "container, vessel," from Latin canna "reed," also "reed pipe, small boat;" but the sense evolution is difficult.
Modern "air-tight vessel of tinned iron" is from 1867 (can-opener is from 1877). Slang meaning "toilet" is c.1900, said to be a shortening of piss-can. Meaning "buttocks" is from c.1910.