The Proto-Indo-European word *sweh₂d-u-
Word *sweh₂d-u-
Meaning sweet
See also Ancient Macedonian: ἡδυλίζειν ‘to flatter’

Comments
Eng. swēte/sweet, Gk. hēdus, Lat. suāvis, Gaul. Suadurīx, Polish słodki, Gm. suozi/süss, ON sötr, Welsh chwant, Ir. sant/, Skr. svādu, Lith. sūdyti, Av. xʷ āsta, Goth. sutis, Toch. swār/swāre

Other words that might be of interest
*h₃em- ‘bitter’, *kwat- ‘sour’, *h₂em- ‘raw, bitter’, *(s)terh₁- ‘stiff’, *suhₓros ‘sour, acid’, *st(h₂)eug- ‘stiff’, *h₂emros ‘bitter, sour’