What is not essential; unimportant what is not requisite; what is informal; as, an immaterial averment, an immaterial issue. 2. When a witness deposes to something immaterial, which is false, although he is guilty of perjury in foro conscientiae, he cannot be punished for perjury. Not material, essential, or necessary; not Important or pertinent; not decisive. Immaterial averment. An averment alleging with needless particularity or unnecessary circumstances what is material and necessary, and which might properly have been stated more generally, and without such circumstances and particulars; or, in other words, a statement of unnecessary particulars in connection with and as descriptive of what is material. Immaterial issue. In pleading. An issue taken on an immaterial point; that is, a point not proper to decide the action.