(an example, instance, of) a changed or different condition

something made different; alteration

(in the event of) a serious and dangerous happening or situation needing quick action

crisis, danger

(an instance of) serious suffering; difficult conditions

personal burden

(an instance of) inventing, using, new ideas, methods

change, novelty

(an instance of) a change in the basic structure of a living or developing organism which can affect the shape, size etc

metamorphosis

the quality of being new or strange; a previously known or unfamiliar thing, idea etc

newness, originality

something that stops progress or makes it difficult

impediment, barrier

an unpleasant situation from which escape seems difficult

difficult situation

strict enforcement (of rules etc); harsh; severe conditions

strictness, exactness

a narrow passage of water connecting two seas; trouble; difficulty

crisis, difficulty