A noun appearing as G. manc “grip, grasp, hold” in the Gnomish Lexicon of the 1910s, likely based on the early root ᴱ√maχā (GL/55); compare ᴱ√MAHA “grasp” from the contemporaneous Qenya Lexicon (QL/57).
Neo-Sindarin: Since √MAH survives as the root of “hand” words in Tolkien’s later writings, I would retain ᴺS. manc “grip, grasp, hold” for purposes of Neo-Sindarin, though its exact derivation is no longer clear.
A verb in the Gnomish Lexicon of the 1910s glossed “grip, seize, lay hold of” based on G. gen “closed hand, grip” (GL/38).