Are there any pairs of English words that are cognate to each other yet have opposite meanings?

Solution 1:

Just thought of another possible example: ward and guard. There are quite a few w- words in English that have a French gu- doublet: warranty and guarantee, warden and guardian, William and Guillaume, war and guerre. From what I can gather, the Germanic w- is the older sound, the gu- variations developing later in France, and introduced into English with the Norman invasion.

But for our purpose: guard means to defend, whereas a ward is someone who is being defended (as in a “ward of court”). Like my previous suggestions, these words aren’t quite antonyms, but they do have opposing meanings. Sort of.

Solution 2:

I love this kind of thing. I came across cognates and doublets when studying linguistics at university. I like Phil Sweet’s suggestion of fox and vixen. I can only think of a couple of suggestions, and I’m not entirely sure they will meet your criteria, Kyle O’Brien, but I’ll post them for what they’re worth (if anyone is still following this thread).

• potion / poison—my (admittedly rather thin) argument being that poison is always something harmful, lethal, whereas potions are, or rather were, usually curatives, concocted back in the day by the local white witch of the village to treat some ailment or other;

• cannabis / hemp / canvas—cannabis is the plant cultivated for its medicinal and recreational properties; hemp is the material made from the plant, which contains no cannabinoids; and canvas, a more general term for cloth or fabric, also happens to derive from the same root (Greek: kannabis) so I thought I would add it as well.