Strong's Definition
a primitive root; properly, to be broken up (with any violent action) i.e. (figuratively) to fear
KJV Usage: be grevious (only Isa. 15:4; the rest belong to 7489)
STEPBible — Tyndale Abridged Hebrew Lexicon
יָרַע (ya.ra) — be ill. (Qal) to tremble, quiver
UBS Dictionary of Biblical Hebrew
verb
Unsteady | verb qal
to quiver exact meaning unknown: = process by which the body trembles as a result of fear or distress
UBS Dictionary of Biblical Hebrew © United Bible Societies, licensed CC BY-SA 4.0.
Brown-Driver-Briggs Hebrew Lexicon
[יָרַע] vb. quiver—Qal Is 15:4 ref