Fláh

According to the Old English Dictionary:

fláh

adj. Insidious, artful, deceitful, fraudulent; subdŏlus, fraudŭlentus, infestus :-- Ðonne ðæt gecnáweþ fláh feónd gemáh when the deceitful impious fiend knows that, Exon. 97a; Th. 362, 19; Wal. 39. flah