producing little or no profit or gain; "deposits abandoned by mining companies as unprofitable"

without profit or reward; "let us have no part in profitless quarrels"- D.D.Eisenhower; "How weary, flat, stale, and unprofitable / Seem to me all the uses of this world"- Shakespeare

To present participles which come from intransitive verbs, or are themselves employed as adjectives, to mark the absence of the activity, disposition, or condition implied by the participle;

not worth using