Longman Dictionary of Contemporary English
hillwalking
noun
EXAMPLES FROM CORPUS
▪ I found the Vulcan to be a highly versatile jacket - great for hillwalking, spring skiing and everyday use.
▪ It was a warm and sunny day; perfect conditions for hillwalking and camping.
▪ Swallow's interests away from work lie in such outdoor activities as skiing and hillwalking, as well as playing squash.
▪ They are well cut, flexible, pleasant to wear, and excellent for summer hillwalking.
Wiktionary
hillwalking
n. (context British Irish English) A pastime of walking in hilly countryside.