A verb appearing as go-bab “shake” in the Early Noldorin Grammar of the 1920s, base on (ancient?) ᴱN. pap and equivalent to ᴱQ. qasa- (PE13/132). I think pap is an ancient Noldorin form, since it does includes the ancient sound change whereby ancient kw [q] became p, but does not include the soft mutation of the second p to b.

In PE13, the editors suggested that the related Qenya verb might be ᴱQ. qapa- “chaffer, bargain, swap, barter” from the Qenya Lexicon of the 1920s (PE12/76), but I believe it is more likely to be ᴱQ. qap- “throb, flutter” from the Early Qenya Phonology of the 1920s (PE14/66), a document that was published a couple years after PE13. See also G. paptha- “tremble” from the Gnomish Lexicon of the 1910s (GL/63), a possible precursor based on the early root ᴱ√PAPA.

Neo-Sindarin: Since I retain ᴺ√PAP “tremble” as a Neo-Root, I would retain ᴺS. gobab- “to shake” based on that root rather than √KWAP. A possible alternative is ᴺS. pasta- “shake”; see that entry for details.