Is it ensure, insure, or assure?
mid-14c., nasalized variant of tagilen "to involve in a difficult situation, entangle," from a Scandinavian source (cf. dialectal Swedish taggla "to disorder," Old Norse þongull "seaweed"). In reference to material things, from c.1500. Meaning "to fight with" is American English, first recorded 1928. Related: Tangled; tangling. Tanglefoot (1859) was Western American English slang for "strong whiskey."
1610s, "a tangled condition," from tangle (v.).