"nightmare"

[Jon Patrick]

    So once again, based on this much at least, it seems the "mare" (in
    nightmare) is a Germanic-Slavic thing.  And though the word may be
    reconstructible as IE, its meanings and usage appear to be too local and
    complex to justify seeing it as IE.  (Of course, I don't know how this
    whole idea ran in Basque.)

The common contemporary word in Basque is "amesgaizto"  which translates as
"bad dream". I'm unaware of any older expression that might shed light on the
current discussion

Jon Patrick
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