very bad or unpleasant
infernal - terrible
The word ‘infernal’ was originally used to refer to things that relate to hell. It has since been adapted to express anger and annoyance at anything that is deeply unpleasant or irritating. With regards to speech, the term has become somewhat old-fashioned, but it still commonly appears in written English, particularly in literature.
There’s a loud party going on next door while I’m trying to work from home. That infernal racket is making it impossible to concentrate!
Frank keeps coming over to my desk to ask for help because he’s too lazy to figure it out for himself. What an infernal nuisance he is!
Working on a construction site is extremely laborious in this infernal weather. It is absolutely sweltering!