A verb appearing as G. manca- “grab, seize” in the Gnomish Lexicon of the 1910s, a verb form of G. manc “grip, grasp, hold” (GL/55).
Neo-Sindarin: Since I retain ᴺS. manc “grip, grasp, hold” for purposes of Neo-Sindarin, I would retain its verb form as well, but adapted as ᴺS. manga- since medial nk > nch > ng in later iterations of the language. I would also adjust its meaning to “grab, ✱grip, hold” to better match the noun, and would instead use ᴺS. mab- for “seize”.
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.