Red beard
Jews are often said to have red beards, even though real Jews do not have red beards very often. Since many aristocrats permanently live & hide as “Jews”, and even recruit spying agents from actual Jews, this may be a spook joke. The pun may be of dqn-ˀdm “red beard” with dq-n-dmˀ “watchman in disguise”.
Hebrew, Aramaic dqn = beard; dq-n = watchman, observer
דקן dqn :
beard, bearded chin, hair-growth
— Hebrew (Jastrow)
דוק dwq :
observation, sight; spectacle; observer, watchman; implication
— Aramaic (CAL)
ܕܝܩܘܢܐ dyqwnˀ :
an observer, a looker-on, an onlooker, one who pays attention to something
— Syriac (AAF)
Hebrew ˀdm = red; dmˀ = resemble, disguise
אדם ˀdm :
red
— Hebrew (Klein)
דמא dmˀ :
resembling, like; to be like, to take an example; to appear in the disguise of
— Hebrew (Jastrow)