i Register
In some senses, painfully is marked as informal. Watch for register when choosing this word.
adv
In a painful manner; as if in pain.
I limped painfully down the stairs.
The unsufficiency and uncandidness of his answer became painfully apparent in the dead silence of the room.
Badly; poorly.
That was the most painfully sung rendition of “Fly Me to the Moon” that I’ve ever heard.