Yes, SAINFOINS is a Scrabble word!

Letter values in Scrabble US: S 1, A 1, I 1, N 1, F 4, O 1, I 1, N 1, S 1.

Is it a valid word?

SAINFOINS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

Eurasian perennial herb having pale pink flowers and curved pods; naturalized in Britain and North America grasslands on calcareous soils; important forage crop and source of honey in Britain

Also: holy clover, onobrychis viciifolia, onobrychis viciaefolia.

Not playable in Scrabble US: SANFOIN, ESPARCET.