Collocations for united - adj.

be, seem, stand
Our nation needs to stand united.

become
remain

closely, firmly
absolutely, entirely, fully, totally
The members of the team were absolutely united in their common goal.
obstacles to a fully united Europe

largely
legally, politically
a politically united federation

against
Everyone was united against a common enemy.

in
united in their aims

with
We ask others to stand united with us.

United is used with these nouns:
action, front, nation