Denshi Jisho — Online Japanese dictionary

何 なに 1: what;
2: (Noun) (Colloquialism) euph. for genitals or sex
Common word, Interjection, Pronoun, No-adjective 
何 なん 1: what;
2: (Prefix) how many (some counter);
3: (Noun) (Colloquialism) euph. for genitals or sex
Common word, Interjection, Pronoun, No-adjective 
幾何 きか geometry
Common word, Noun 
如何 どう how; in what way; how about
Common word, Adverb, Usually written using kana alone 
如何 いか how; in what way; how about
Adverb, Usually written using kana alone 
如何 いかが how; in what way; how about
Common word, Adverb, Usually written using kana alone 
如何 いかん 1: how; in what way;
2: (Noun) circumstances
Common word, Adverb 
奈何 いかん 1: how; in what way;
2: (Noun) circumstances
Adverb 
誰何 すいか challenging (an unknown person); asking a person's identity
Noun, Suru verb 
幾何 いくばく how many; how much
Adverb, Temporal noun 
何何 なになに 1: such and such (when being vague, placeholder, etc.); this and that;
2: (Interjection) What?; What is the matter?; What are the items?
Pronoun, No-adjective 

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