9 Grammatical Pitfalls
"vigor, energy," 1912, shortened form of pepper (n.), which was used in the figurative sense of "spirit, energy" from at least 1847. Pep rally is attested from 1945; pep talk from 1926. To pep (something) up is from 1925.
To stimulate; energize; brighten; JAZZ something UP: Pep up your winter wardrobe (1925+)