c. 1300, "heavily," also "solidly," from sad + -ly (2). Meaning "sorrowfully" is mid-14c.
sadly he died before he could see his grandchild
`She died last night,' he said sadly
he was sadly neglected
Sadducee
Sadie
sadism
sadist
sadistic
sadly
sadness
sado-masochism
sado-masochist
safari
safe