An issue for the HSE? One is better off without it! (8)

I believe the answer is:

sickness

I'm a little stuck... Click here to teach me more about this clue!

'it' is the definition.
The definition suggests a singular noun which matches the answer.

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for sickness that I've seen before include "State of being ill" , "It's not looking good" , "Ailment" , "Illness, disease" , "State of ill-health, malady" .)

I've seen this clue in the Irish Times and the Irish Times (Crosaire).

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.