Refers to a thing used in place of another, often with a nuance of being a stand-in or makeshift alternative.
I used synthetic leather as a substitute for real leather.
payment in substitutes; accord and satisfaction; substitute performance
Compound of 代 (だい, 'substitute') and 物 (ぶつ, 'thing'). The reading ぶつ for 物 is a common Sino-Japanese reading used in compounds.