act as

verbs

function as or act like

"This heap of stones will act as a barrier"

act as

is a type of (narrower)

serve a purpose, role, or function

"The tree stump serves as a table"; "The female students served as a control group"; "This table would serve very well"; "His freedom served him well"; "The table functions as a desk"

function, serve

pretend to have certain qualities or state of mind

"He acted the idiot"; "She plays deaf when the news are bad"

act, act as, play