Nouns

(n)affirmativea reply of affirmation“he answered in the affirmative”

Adjectives

(a)affirmative, affirmatoryaffirming or giving assent“an affirmative decision”, “affirmative votes”
(s)affirmative, optimisticexpecting the best“an affirmative outlook”
(s)approving, affirmative, approbative, approbatory, plausiveexpressing or manifesting praise or approval“approbative criticism”, “an affirmative nod”