Qenya
palpa-
verb. to beat, batter; *to clap, applaud (with palms)
Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!
A verb glossed “to beat, batter” in The Etymologies of the 1930s under the root ᴹ√PALAP (Ety/PALAP). It replaced ᴹQ. pal-, palap- “beat” based on a (rejected) shorter form of the root: ᴹ√PAL “beat” (EtyAC/PAL²).
Conceptual Development: Early Qenya Word-lists of the 1920s had ᴱQ. panta- “to beat” (PE16/142), the Early Qenya Grammar had ᴱQ. tanga- “beat” (PE14/58), while the Qenya Lexicon of the 1910s had ᴱQ. lampa- “hit, beat” (QL/51). ᴹQ. palka- “beat flat” from 1948 might be a later variant; see that entry for details.
Neo-Quenya: In a post on Vinyë Lambengolmor Discord Server (VLDS) in 2023-08-20, Röandil suggested this verb might also be used for “to clap, applause” in combination with Q. paltar “palms”, as in palpa paltar = “to clap, (lit.) beat palms”. I personally think the dual would be more likely: palpa paltu. See also the extended meaning of [ᴺQ.] patahta- “clatter”.