Synonyms of 'muscle in'
If one thing encroaches on another, the first thing spreads or becomes stronger, and slowly begins to restrict the power, range, or effectiveness of the second thing.
He doesn't like people to encroach on his territory.
Thesaurus for muscle in from the Collins English Thesaurus
If someone muscles in on something, they force their way into a situation where they have no right to be and where they are not welcome , in order to gain some advantage for themselves.