[†A.] 1. Forming a conjunctional phrase introducing a case in which an exception to a preceding negative statement (expressed or implied) will or may exist: (not) on a less or lower condition, requirement, etc., than (what is specified). Obs[olete].
- Exercise, unless you spurn healthfulness.
that ought to mean:
- Exercise, if you spurn not healthfulness.
Here's the snag. If I substitute 1 into 2, then 2 becomes:
- Exercise, (not) on a less or lower condition, requirement than you spurn healthfulness.
But how does 4 signify the same as 3?