Willingly or not; anyhow, any old way. This very old term was once will-he, nill-he, nill being the negative of will (i.e., will not or won’t). It was in print by the late thirteenth century and was picked up by numerous writers, including Shakespeare (in Hamlet). Today it is sometimes used in the original sense—that is, this will happen, whether or not one wants it to—and also (erroneously according to the OED but not American dictionaries), in the meaning of sloppily or in disorganized fashion.