by indirect reference
131allusion — [ə lo͞o′zhən, alo͞o′zhən] n. [LL allusio, a playing with < allusus, pp. of alludere: see ALLUDE] 1. the act of alluding 2. an indirect reference; casual mention …
132allusiveness — noun a quality characterized by indirect reference • Derivationally related forms: ↑allusive • Hypernyms: ↑indirectness …