needing and using much energy and thought

difficult, hard to endure

exhausting

difficult, taxing

needing, showing, great effort

hard, difficult

needing much effort

difficult; requiring hard labor

long, tiring and not interesting

dull, monotonous

annoying

irritating, exasperating

causing tiredness, exhaustion, impatience etc

difficult, bothersome

not enjoyable

boring, uneventful

not entertaining

boring, uneventful

tiring; long and dull

burdensome