1. A word expressing contrast or opposition between two phrases.
unless / ənles /
ETYM Formerly, onles, onlesse, onlesse that, that is, in less, in a less case. Related to On, and Less.
1. Upon any less condition than (the fact or thing stated in the sentence or clause which follows).
2. If not; supposing that not; if it be not; were it not that; except.