grass rootsplural noun
also grassroots us/ˈɡræs ˈruts, ˈrʊts/the ordinary people in a society, movement, or organization:
She spent years trying to design education policy from the grass roots up.
grass-roots
adjective [ not gradable ] also grassroots us/ˌɡræsˌruts, ˈrʊts/
a grass-roots movement