Where does “drearisome” come from?

drearisome (English) comes from English some, from Middle English som, from Old English sum, from Proto-West Germanic *sum, from Proto-Germanic sumaz, from Proto-Indo-European sem- — together, one.

drearisome (English): Very dreary

Definitions

Very dreary

Ancestry of “drearisome”, step by step

drearisome traces back through two separate lines of ancestry.

via English some

Step	Language	Word	Meaning
1	English	some	A certain number, at least two; An indefinite...
2	Middle English	som	some
3	Old English	sum	some
4	Proto-West Germanic	*sum	some
5	Proto-Germanic	sumaz	some (one), a certain (one)
6	Proto-Indo-European	sem-	together, one

via English dreary

Step	Language	Word	Meaning
1	English	dreary	Drab; dark, colorless, or cheerless; Grievous,...
2	Middle English	drery	Experiencing sadness; glum, unhappy; Showing...
3	Old English	drēoriġ	sad
4	Proto-Germanic	dreuzagaz	bloody; gory; sad
5	Proto-Indo-European	dʰreus-	to break, break off, crumble

Every word from Proto-Indo-European sem- →Every word from Proto-Germanic sumaz →Every word from Proto-West Germanic *sum →