Early Quenya
satwa
adjective. hollow, dug-out, excavated
nôf
adjective. hollow
ronta
adjective. hollow
rotwa
adjective. hollow
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!
An adjective appearing as ᴱQ. satwa “hollow, dug-out, excavated” in the Qenya Lexicon of the 1910s under the early root ᴱ√SAPA “dig, excavate” (QL/82). It is likely the result of the Early Qenya sound change whereby [[eq|[pw] became [tw]]] (PE12/23).
Neo-Quenya: In the rare cases where ancient pw occurred Quenya of the 1930s and later, it became pp (PE19/43, 86). Thus I would update this Early Qenya adjective to ᴺQ. sappa “hollow, dug-out, excavated”.