2820  chasak  khaw-sak'

 a primitive root; to 
restrain or (reflex.) 
refrain; by implication, to 
refuse, spare, preserve; also 
(by interch. with 2821) to 
observe:--assuage, X darken, 
forbear, hinder, hold back, 
keep (back), punish, refrain, 
reserve, spare, withhold.

 see HEBREW for 02821