The verb for “to eat” derived from the root √MAT of the same meaning (VT39/7).
Conceptual Development: This verb and root are quite well established, dating all the way back to ᴱQ. mat- and ᴱ√MATA of the Qenya Lexicon of the 1910s (QL/59) and appearing as ᴹQ. mat- and ᴹ√MAT in The Etymologies of the 1930s (Ety/MAT), as well as numerous other places albeit with occasional variants like mata- (PE12/26). This verb was one Tolkien often used in examples of verb conjugations and as such its inflected forms changed considerably over time, but that is more a topic of the evolution of the Quenya verb system itself.
luxo (luxu-) noun "mud" (QL:56)