An orthographical variation of chaphah; properly, to cover, i.e. (in a sinister sense) to act covertly -- do secretly.
see HEBREW chaphah
H2644. chapha
[חָפָא] verb do secretly (properly cover, = חפה, q. v.); — only
Pi`el Imperfect וַיְחַמְּאוּד֗֗֗ברים and they did things secretly 2 Kings 17:9.