off-peak

adjective

1. of, relating to, or during a period of less than maximum frequency, demand, intensity, or use: the off-peak travel season; off-peak train fares.
2. lower than the maximum: off-peak production.

adjective

1. of or relating to services as used outside periods of intensive use or electricity supplied at cheaper rates during the night

adj.1906, originally in reference to electrical systems, from off (adv.) + peak (n.).