teach /ˈtiːtʃ/ verb
teaches; taught /ˈtɑːt/ ; teaching
teaches; taught /ˈtɑːt/ ; teaching
Learner's definition of TEACH
: to cause or help (someone) to learn about a subject by giving lessons
[+ object]
[no object]
[+ object] : to give lessons about (a particular subject) to a person or group
[+ object] : to cause or help (a person or animal) to learn how to do something by giving lessons, showing how it is done, etc. often followed by to + verb
[+ object] : to show someone how to behave, think, etc.
[+ object] informal : to cause (someone) to know the unpleasant results of something

you can't teach an old dog new tricks

see 1dog