>>There IS a difference between second hand and second-hand (as in pre-owned as it's euphemistically said nowadays)
>
>The different spelling isn't really enforced,

Well it bloody-well should be.

>and when spoken you can't tell anyway.

Well in the case of second-hand there's more likely only a barely perceptible gap between the words, probably with the "h" and possibly the "d" being dropped (in England), as "secon' 'and", whereas one would take the trouble to say "Look at the second hand on the clock"

>
>Is there an euphemism for "euphemism"?

Well it doesn't need one. BTW I once looked up "iambic pentameter" and found both words separately, each being defined by the other, in like a recursive definition.