substitutesub·sti·tute1 /ˈsʌbstətjuːt-tuːt/ noun [countableC]1something new or different that can be used instead of something elseSugar substitutes are used by the soft drinks industry.
substitute forTraining is important but it is no substitute for (=cannot take the place of) experience.
2HUMAN RESOURCESJOBsomeone who does someone else’s job for a limited period of timeWe need to find a substitute while she is sick.
—substitute adjectiveadj [only before a noun]Plastic is sometimes used as a substitute material.
a substitute driver