n. 25B6; noun substitutes for permanent employees : REPLACEMENT, deputy, relief, proxy, reserve, surrogate, cover, stand-in, locum (tenens), understudy; informal sub.
25B6; adjective a substitute teacher : ACTING, replacement, deputy, relief, reserve, surrogate, stand-in, temporary, caretaker, interim, provisional.
permanent.
25B6; verb
curd cheese can be substituted for yogurt : EXCHANGE, replace with, use instead of, use as an alternative to, use in place of, swap.
the Senate was empowered to substitute for the President : DEPUTIZE, act as deputy, act as a substitute, stand in, cover; replace, relieve, take over from; informal sub, fill someone's boots/shoes.