Proto-Basque: *labain-
Meaning: 1 to slip, slide 2 to polish, furbish (something) 3 slippery 4 flatterer 5 knife, razor 6 whetstone
Bizkaian: laban 3, 4, laban-du 1, 2, labana, labaiña 4
Gipuzkoan: laban, labain 3, 4, labana 4, 5, laban-arri 6
High Navarrese: labaiña 5
Comments: For the semantic connection of 'slip, slide > rub > polish, whet' cf. German schleifen, Scheifenstein, etc. Bsq retains an archaic syllabic structure, *labaɨ-n- < *ʎāwE-n- or the like, remodeled in PNC as *ʔāʎwE. There may be some contamination with reflexes of Lat. novacula ‘razor’ > Cat. navalla, Port. navalha, Sp. navaja; cf. the eastern Bsq loanwords (ZBR) nabéla, (RNC) ñabla, (SAL) nabla ‘razor’.
