There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
sampe
noun. cave, hollow
sampo
noun. cave, hollow
sapa-
verb. to dig
A verb appearing as ᴱQ. sapa- “dig” in the Qenya Lexicon of the 1910s under the early root ᴱ√SAPA of the same basic meaning (QL/82). The verb ᴱQ. sap- “dig” reappeared in Early Qenya Word-lists of the 1920s (PE16/145).
Neo-Quenya: Since the root √SAP appeared in Tolkien’s later writing, I would retain ᴺQ. sap- “to dig” for purposes of Neo-Quenya.
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
A noun in the Qenya Lexicon of the 1910s glossed “cave, hollow” with variants sampe and sampo derived from the root ᴱ√SAPA “dig, excavate” (QL/82), both variants also appearing in the Poetic and Mythological Words of Eldarissa with the gloss “cave” (PME/82).