ʿālas עָלַס ‘to rejoice’ (Hebrew)

Etymology^?: a primitive root

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