fickle

【原文】
Some hospitality analysts say figuring out this fickle demographic may not be easy. While youth hostels exist to some degree in most major U.S. cities, they have never caught on as they have in Europe, where sharing rooms with strangers is more common.

【単語の意味（日本語）】
気まぐれの

【その他の単語】
catch on ～を受け入れる