Whether or not
This and/or that. Whatever is in the set, and everything outside it. The first, the last, the everything. Alpha, omega and everything in between.
The very first word in redundancy, and the last in profound ontological uncertainty.
See also
Plain English Anatomy™ Noun | Verb | Adjective | Adverb | Preposition | Conjunction | Latin | Germany | Flannel | Legal triplicate | Nominalisation | Murder your darlings