n.a commercial principle that without a warranty the buyer takes upon himself the risk of quality
英汉双解大词典
caveat emptor/ˈɛmptɔː/
1.
CONVENTION（习惯表达） Caveat emptor means "let the buyer beware," and is a warning to someone buying something that it is their responsibility to identify and accept any faults in it. 买方自慎; 货物售出，概不退还 [FORMAL, WRITTEN]