"commendation, sanction," 1680s, from approve + -al (2). According to OED, "Rare bef. 1800; now generally used instead of" approvance, which is attested by 1590s, from French aprovance.
Entries linking to approval
approve v.
c. 1300, apreven, approven, "to demonstrate, prove," from Old French aprover (Modern French approuver) "approve, agree to," from Latin approbare "to assent to as good, regard as good," from ad "to" (see ad-) + probare "to try, test something (to find if it is good)," from probus "honest, genuine" (see prove).
The meaning was extended by late 14c. to "regard or assent to (something) as good or superior; commend; sanction, endorse, confirm formally," especially in reference to the actions of authorities, parliaments, etc. Related: Approved; approving.
-al 2
suffix forming nouns of action from verbs, mostly from Latin and French, meaning "act of ______ing" (such as survival, referral), Middle English -aille, from French feminine singular -aille, from Latin -alia, neuter plural of adjective suffix -alis, also used in English as a noun suffix. Nativized in English and used with Germanic verbs (as in bestowal, betrothal).
disapproval n.
"act or fact of disapproving, dislike," 1660s; see disapprove + -al (2), though it might as well be from dis- + approval.