Popular
Folk, Working Class
な adjective
Remember how 庶民 means "common people?" Well when all the common people like something it becomes popular!
しょみんてき
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
ここの饂飩はこの庶民的な味がいいんだよ。
The humble taste of the udon here is good.