step in vs deputize

step in and deputize both are verbs.

Word	Noun	Adjective	Verb	Adverb
step in	No	No	Yes	No
deputize	No	No	Yes	No

As verbs, step in and deputize are synonyms defined as:

Other synonyms of step in include deputise, substitute.

step in (verb)	deputize (verb)
get involved, so as to alter or hinder an action, or through force or threat of force	appoint as a substitute
act as a substitute	act as a substitute