Sometimes people are warned of slippery surfaces with signs saying "slippery when wet". I would like to know how to phrase such a sign in Latin. Translating a full sentence is easier:
This road is slippery when it is wet.
Haec via lubrica est quando madida est.
This might not be perfect, but I think it works. (Feedback is welcome.) The thing I have trouble with is squeezing this into a more concise form suitable for a sign.
In English one would write "slippery when wet", and in Finnish (directly translated to English) "slippery as wet", and I guess other languages have other constructions. Therefore I see no obvious choice of structure in Latin.
Like many Latin adjectives, madidus has a corresponding verb: madere. Using that, I would write lubricus madens. Is this a good way to phrase it, or is there something better?
I would also like to know how to do this for adjectives without a verb. How can I translate short expressions of the form "<adjective> when <adjective>" if there is no corresponding verb? I don't know a suitable structure.