A frequentative verb in the Quenya Verbal System (QVS) from 1948, based on ᴹQ. hlik- “creep” and so meaning “sneak about” (PE22/113). Tolkien gave its ancient form as sillikk derived from the root ᴹ√SLIK and its modern form as lilhikke [the correct reading according to the editors, PE22/113 note #78]. In normal Quenya orthography we would expect *hl rather than lh, and based on the discussion of frequentatives we’d expect a final vowel a, as in ᴹQ. sisilla-. So perhaps *lihlikka- is a more plausible form.