With names there are various possibilitis, among them CLAP-XAD, and there
is indeed CALAP in Neh. 3:30. The roor CLP came into use in post-biblical
Hebrew, in the sense, I believe, of 'draw-out' (in modern Hebrew
literature CALAP is a 'sharp shooter').
The root CLP is a variant, methinks, of the roots (I am unable at the
present time to use Hebrew script)
DLP, ZLP, TLP (with a tet), YLP, SLP, CLP, SHLP.
Hence CLAP-XAD is possibly 'the drawer-out (SHALAP) of a sharp (XAD) one'.