A primitive root: to shudder (more or less violently) -- tremble.
H7460. raad
[רָעַד] verb tremble, quake (Late Hebrew id., Hiph`il shake (rare), רְעָדָה a trembling, shaking; Arabic thunder (said of sky), VIII. tremble, quiver; Ethiopic tremble; Jewish-Aramaic רְעַד tremble, shake); —
Qal Imperfect3feminine singular וַתִּרְעָ֑ד Psalm 104:32 and it (the earth) trembleth at the gaze of ׳י, in theoph.
Hiph`il Participle מַרְעִיד עָמַדְתִּי Daniel 10:11 I stood trembling; plural מַרְעִדִים Ezra 10:9, with יָשַׁב.