A verb appearing in the Early Qenya Phonology of the 1920s with glosses “throb, flutter”, derived from ᴱ✶ku̯ap- as an elaboration of ᴱ√kapa “leap” (PE14/66). Oddly, Tolkien gave it the primitive form ᴱ✶skapi̯a-. The verb qap- might be a later iteration of ᴱQ. papa- “tremble” from the Qenya Lexicon of the 1910s (QL/72). Compare also the possibly related verb ᴱN. gobab- “shake” (PE13/132).
Early Quenya
qapa-
verb. to chaffer, bargain, swap, barter
qap-
verb. to throb, flutter
A verb appearing as ᴱQ. qapa- “chaffer, bargain, swap, barter” in the Qenya Lexicon under the early root ᴱ√QAPA “chaffer” [= haggle] (QL/76).
Neo-Quenya: I would retain ᴺQ. quap- “chaffer, bargain, swap, barter” for purposes of Neo-Quenya derived from a Neo-Root ᴺS. √KWAP, since we otherwise have very few words having to do with commerce.