substitute teach
/ˌsʌbstɪtjuːt ˈtiːtʃ/ /ˌsʌbstɪtʃuːt ˈtiːtʃ/originally and chiefly US
verb
[no object] To work as a substitute teacher. Also with object: to teach (a lesson, subject, etc.) as a substitute teacher.
Origin
1950s. From substitute + teach, after substitute teacher.