Cleansing agents remove dirt, grease, microbes or stains from a surface and help carry them away in water.
The most important cleansing molecules are surfactants, or surface-active agents, which reduce the surface and interfacial tension of water.
Soap is a specific class of surfactant made from salts of long-chain fatty acids.
A synthetic detergent is a formulated cleaning product whose main surfactants are usually synthetic compounds such as alkyl sulphates, alkylbenzene sulphonates or ethoxylated alcohols.