עָלַס ʻâlaç (H5965)

to leap for joy, i.e. exult, wave joyously

1) to rejoice 1a) (Qal) to rejoice 1b) (Niphal) to exult 1b1) to flap joyously (of ostrich) 1c) (Hithpael) to delight oneself

a primitive root;