This is the 618th most frequent Czech word.
místních
"Of the locals" or "local (plural, genitive/locative case)."
Here, 'místních' acts as a genitive plural form of the adjective, related to 'obyvatel' (residents), indicating possession or relation.
Tradice byly ovlivněny místních obyvatel.
The traditions were influenced by the local residents.
In this case, 'místních' is used in instrumental form and relates to an unspoken noun in the context, indicating 'local people.'
Restaurace je oblíbená mezi místních.
The restaurant is popular among the locals.
In this sentence, 'místních' is used as an adjective modifying 'lidí' (people), describing them as local.