Inside is the opposite if outside. Logically. So, the opposite of hangover must be hangunder then? And the positive of disappointed is appointed? The ‘un’ and ‘um’ prefixes are easier though. Simply a matter of sound, phonetics and clear logic. An umbrella can’t be an unbrella now can it? And umbridge is not a hesitation in crossing a river.
It does get a bit trickier though with some of these incomprehensible prefixes and suffixes that sound so simple. Less is naturally the antonym of more. So if one is unfortunate enough to be hapless, one would certainly want to become hapmore. Or if you are homeless, do you wish to be homemore, or maybe homeplus? Furthermore or furtherless, moreover. More or less.
Be is one of my favourite prefixes because it is so stupidly also the most common verb in English. Clever idea really. But what does it mean? All over and all around? Completely or having or covered with? Perhaps affected with or caused to be? Now there’s another wonderful piece of logic and clarity. Beset, becalmed, bejeweled, bespectacled, befog, bemuse, bewitched, bespatter but never bebe! And may it be a suffix in maybe?
Not negates a verb and is not a prefix. Notwithstanding what I just wrote, remember that.
Perhaps a little addition with a-, ac-, ad-, af-, ag- al-, an-, ap-, at- as-, at- ? No I think I’ll pass on that one.
Probably better to stop here and enjoy my impeachable and unintoxicated state of hangunderness!