Difficult to do and involving a lot of effort
difficult adjective
not easy to do, deal with, or understand
hard adverb
using a lot of effort
tough adjective
difficult
demanding adjective
needing a lot of time, ability, and energy
challenging adjective
difficult to deal with or achieve, but interesting and enjoyable
arduous adjective
extremely difficult and involving a lot of effort
taxing adjective
difficult, and needing a lot of physical or mental effort
gruelling adjective
very difficult and involving a lot of continuous effort
complicated adjective
difficult to do, deal with, or understand, especially because of involving a lot of different processes or aspects
be an effort phrase
to be difficult, tiring, or boring to do