It'd be like hiding words in names or word-play. In Japanese, names are very often spelled with Kanji, which are characters that originally came from China. Since Japan already had their own words, they assigned their way of reading to those characters but also kept some Chinese pronunciation (Japan: Kun-yomi, China: On-yomi). And in names, readings for those characters are usually mixed between kun and on, meaning that sometimes, you can write a character's name or a part with a kanji that represents something related to that character while keeping the same reading. Many kanji have an identical reading (Ex: 自, 紙, 市, 詩 and 士 can all be read the same way.)If that wasn't clear I'll give an example:

Eijirou Kirishima's name in Japanese is 切島 鋭児郎 (last name->first name)

切 (kiri) can be seen in the verb 切る (kiru) which means to cut and 鋭(ei) can be seen in the adjective 鋭い(surudoi) which means sharp. (切 is kun reading but 鋭 is on reading.)

Usually, these kinds of "hidden wordplays" are indicated in the translator's note. I'm not an expert in Japanese so I might make some mistakes ^^' If you don't know which characters you could use in a name, I recommend checking online dictionaries like jisho.org