used to refer to something that is inexplicably difficult

problems that a person encounters in the early stages of a project or activity

said of something that is very complex or difficult for one understands or work with

(of a task) to be very difficult or almost impossible to do or complete

a difficult fight or challenge that requires a lot of effort and determination

a task or challenge that requires an immense amount of effort, strength, or endurance to accomplish

a difficult and challenging situation or task that requires significant effort to overcome or complete

used for referring to a situation that causes difficulties for one

to attempt to do something that is beyond one's capability

turning really red in the face because of doing a lot of physical activities

used to describe a job or task that is too difficult or challenging

the hardest or most boring part of a task or job

a situation that is very difficult because one is not prepared to deal with it

to be unable to continue doing something because one has used all one's resources