"of or pertaining to motivation," 1931, from motivation + -al (1).
Entries linking to motivational
motivation n.
1873, "act or process of furnishing with an incentive or inducement to action;" see motivate + -ion. Perhaps borrowed from German, where motivation is attested by 1854. Psychological use, "inner or social stimulus for an action," is from 1904.
-al 1
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)).