يراع

Where it comes from

Probably from Aramaic, the same word as or derivative of יַעְרָא / ܝܰܥܪܳܐ (yaʿrā, “rushes, bushes, thicket”), so doublet of وَعْر (waʕr).

Dietrich, before the Aramaic penetration of Arabic was worked out, drew this word, as though with a certain fossilized ya- prefix found in some organism names, to the root ر ع ع (r ʕ ʕ) to which also well-known رَعْرَاع (raʕrāʕ, “false fleabane”) and رَعَاع (raʕāʕ, “refuse”) belong.

The sense of a coward either way may be instead from the root ر و ع (r w ʕ), though this appears related to the aforementioned root, which Dietrich glossed as zittern (“to shiver”).