怎麼 is listed as an adverb in Wordreference (http://www.wordreference.com/zhen/怎么). Some dictionaries define it as "如何,怎样" (e.g., http://www.zdic.net/cd/ci/9/ZdicE6Zdic80Zdic8E356719.htm), that is to say, an adverb or pronoun. In fact, none of the dictionaries I consulted explain its adjective function under the entry of 怎麼 as if this function is non-standard. Before giving examples of such function, I would first clarify what I mean by "adjective": What are you reading? ==> "What" is an interrogative pronoun. What place did you visit? ==> "What" is an interrogative adjective. What kind of books do you like? ==> "What kind of" is an interrogative adjective. Tell me what kind of books you like ==> "what kind of" (什么样的) is an interrogative pro-adjective. Examples of 怎麼 as an adjective: 明《金瓶梅》: 请你们往他家走走去，就瞧瞧春花儿怎么模样 ==> 怎麼 modifies the noun 模样. 明《金瓶梅》: “六姐，你端的怎么缘故？告我说则个。==> 怎麼 modifies the noun 缘故. 明崇禎陸人龍《型世言》: 縣尊道：“也罷。”叫鄭氏：“你道是怎麼兩個箱？我就押你兩人去取來" ==> 怎麼 modifies 兩個箱. 清李漁《連城璧》:不知是怎麼兩個相貌，都一般有這樣的孝心.==> 怎麼 modifies 兩個相貌. 《红楼梦》: 到底是怎麼個緣故呢？怎麼個寫法兒？不知他是怎麼個情性. 陰陽是怎麼個樣兒？到底怎麼個辦法？ And of course, the later attested 到底是怎麼回事！ (Note:The adjectival function of 怎麼 is absent in 《水浒传》(施耐庵 1296年－1372年)). My Questions: (1) Is there any reason that this adjectival usage is not listed under the entry of 怎麼 by most, if not all, Chinese dictionaries? (2) Is there any semantic difference between 怎么模样 and 什么模样, or between 怎么缘故 and 什么缘故? (3) （清）惜红居士《李公案奇闻》: 閒話少說，到底是什麼個緣故. So, can I say: 什么个概念, 什么个情况, 什么个程序, 什么个意思...., and therefore 什么回事?