extremely bad or of a very low standard (Oxford)
very bad (Cambridge)
His manners are abysmal. (Oxford)
The council has an abysmal record on education. (Oxford)
The food was abysmal. (Cambridge)
The standard of the students' work is abysmal. (Cambridge)
abysmal manners
an abysmal record
an abysmal food
an abysmal standard
Terrible
Bad
Magnificent
Splendid
Abysmally