[Mombro is the same as] Mormo,1 and the bogey/bugbear [sc. of that name].2
Greek original · Adler’s text
Μομβρώ· ἡ μορμώ, καὶ τὸ φόβητρον.
Betacode
*mombrw/: h( mormw/, kai\ to\ fo/bhtron.
Notes (2)
Same entry in Hesychius mu1598 (who also has a similar one at mu1600 for 'Mommo') and Photius, Lexicon mu513 Theodoridis. It is conventional to capitalize all (rather than merely some, as Adler) of these names.