similar, alike, (exactly) the same, indistinguishable, undistinguishable, identical, uniform, of the same kind, twin, interchangeable, undifferentiated, homogeneous, cut from the same cloth, consistent, unvarying;
corresponding, correspondent, commensurate, equivalent, matching, like, parallel, analogous, comparable, cognate, equal
informal like (two) peas in a pod, much of a muchness, (like) Tweedledum and Tweedledee