What does the suffix -fy mean? capable of being full of cause or become the action of

 a verbal suffix meaning “to make,” “cause to be,” “render” ( simplify; beautify); “to become,” “be made” ( liquefy). The suffix was introduced into English in loan words from Old French ( deify), but is also used in the formation of new words, usually on a Latin root ( reify).

-fysuffix1.(added to nouns) forming verbs denoting making or producing."speechify"2.forming verbs denoting the making of a state defined by an adjective."amplify"