The Gnomish Lexicon of the 1910s had a noun lobrob “a gallop - the sound of horse’s feet” as an elaboration of G. lob “run, gallop (of animals)” (GL/54). The meaning of the second element is unclear, but might simply be an onomatopoeic variation of the initial element.

Neo-Sindarin: Since I retain ᴺS. lob- “gallop, *lope” for purposes of Neo-Sindarin, I would retain the noun ᴺS. lobrob as well.