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Etymology
15th century, from, meaning “to seek an [undue] advantage over”.

Verb

 * 1)  to take advantage of; to give someone less than they deserve

Usage notes

 * The sense is somewhat counterintuitive in view of the literal translation “to over-advantage someone”. Accordingly there may be occasional erroneous use of to mean “to take more than one deserves”. (The construction  as such is not erroneous when meaning “to take advantage of each other”.)