Up-hill is a term that describes a slope or incline that goes upward, requiring more effort and energy to climb. However, there are several synonyms for the word "up-hill" that may be used to describe a similar concept. For instance, "ascending" refers to the act of going up or climbing, often in a gradual but persistent way. Similarly, "climbing" suggests a progression upward, while "upward" and "skyward" are adverbs that denote movement or direction towards the sky or upward. Lastly, "steep" is an adjective that describes a slope or incline that is difficult to climb or requires a significant amount of effort and energy.