The Tocharian B word wärs-2
Word wärs-2
IPA wərs
Meaning darken

Comments
Douglas Q. Adams, “Etymological Dictionary of Tocharian B”, 1999, Brill

Other words that might be of interest
kauṃ ‘sun’, pūwar ‘fire’, taur ‘ash, dust’, läkutsetstse ‘bright’, pälk- ‘burn’, pälśalñe ‘burning’, sleme ‘flame’, tsāk ‘illuminate’, parkāsaṃ ‘illumination’, korośāna ‘bright yellow’, yäp- ‘sunset’, skiyo ‘shade, shadow’, pälk ‘shine’