recessional adj.

1640s, "act of receding, a going back," from French récession "a going backward, a withdrawing," and directly from Latin recessionem (nominative recessio) "a going back," noun of action from past-participle stem of recedere "to go back, fall back; withdraw, depart, retire," from re- "back" (see re-) + cedere "to go" (from PIE root *ked- "to go, yield").

The sense of "temporary decline in economic activity" was a fall-of-1929 coinage, probably a noun of action from recess (v.):

The material prosperity of the United States is too firmly based, in our opinion, for a revival in industrial activity — even if we have to face an immediate recession of some magnitude — to be long delayed. [Economist, Nov. 2, 1929]

Ayto ("20th Century Words") notes, "There was more than a hint of euphemism in the coining of this term."

suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -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).