teach (v.)

Old English tæcan (past tense tæhte, past participle tæht) "to show, point out, declare, demonstrate," also "to give instruction, train, assign, direct; warn; persuade," from Proto-Germanic *taikijan "to show" (source also of Old High German zihan, German zeihen "to accuse," Gothic ga-teihan "to announce"), from PIE root *deik- "to show, point out." Related to Old English tacen, tacn "sign, mark" (see token). Related: Taught; teaching.

Lemonade Vendor (Edgar Kennedy), enraged: I'll teach you to kick me!
Chico: you don't have to teach me, I know how. [kicks him]

The usual sense of Old English tæcan was "show, declare, warn, persuade" (compare German zeigen "to show," from the same root); while the Old English word for "to teach, instruct, guide" was more commonly læran, source of modern learn and lore.

Definitions of teach
teach (v.)
impart skills or knowledge to;
I taught them French
Synonyms: learn / instruct
teach (v.)
accustom gradually to some action or attitude;
The child is taught to obey her parents
Teach (n.)
an English pirate who operated in the Caribbean and off the Atlantic coast of North America (died in 1718);
Synonyms: Edward Teach / Thatch / Edward Thatch / Blackbeard