Main Entry: la·ches

Pronunciation: \ˈla-chəz, ˈlā-\

Function: noun

Inflected Form(s): plural laches

Etymology: Middle English lachesse, from Anglo-French laschesce, from lasche lax, ultimately from Latin laxare to loosen — more at lease

Date: 14th century

: negligence in the observance of duty or opportunity; specifically : undue delay in asserting a legal right or privilege