I think I would want evidence in the form of citations before trusting these sources over the OED. The LSJ only gives one online citation for äéáóõñìïò (diasurmos), Diodorus Siculus 14.109.6:

But Dionysius, hearing of the diasurmos of his poems did not leave off his enthusiasm for writing as his flatters said that those who were jealous of all such well written things later admired them. ( My translation)

I think disparagement probably fits better than damning with faint praise here.

Adding link: http://www.perseus.tufts.edu/cgi-bin/ptext?lookup=Diod.+14.109.1

Bingley

Bingley