Synonyms for Probationary:

adj.

all (adjective)
provisionary, provisional, tentative.
experimental (adjective)
provisional, tentative.
tentative (adjective)
acting, provisionary.

n.

blue-collar, emeritus, creative, designate, auxiliary, acting, deputy, budding. associate, assistant, cooperative, collaborative, collegiate, casual, ceremonial, clerical, adjunct, antisocial. probationary (noun)
conditional, provisionary, tentative, provisional.

Other synonyms:

tentative
tentative.