adj.
VERBS
▪ be , prove
▪ make sth
▪
We have changed the course to make it more ~.
▪ find sth
▪
He found the course academically ~.
ADVERB
▪ extremely , fairly , very , etc.
▪ enough , sufficiently
▪
The tasks were not ~ enough for me and I got bored.
▪ academically , intellectually , physically , politically , technically
Challenging is used with these nouns: ↑ job , ↑ look , ↑ question , ↑ target , ↑ task , ↑ work