| Word form | nikoniko |
| Original script | にこにこ |
| LWT meaning(s) | |
| Word meaning | Onomatopoetic referring to smiling. Typically used as an adverb, as in nikoniko warau “laugh smilingly”. Original meaning “soft”, attested i(n present meaning in mid-Muromachi. nikkori (1563) |
| Analyzability | semi-analyzable |
| Gloss | niko~niko ADV~? |
| Age | Middle Japanese [21] (1185–1603) |
| Lexical stratum | giongo |
| Year | 1244 |
| Register | General |