Portuguese loanwords in Japanese are interesting because, unlike other Western word imports, a lot of them have been around long enough, and thoroughly integrated into the culture and writing system, that a number of them are assumed to be Japanese or Sino-Japanese words by most all native speakers.

Tenpura (commonly seen as 天麩羅 or 天婦羅) is one example, but also karuta (a card game, commonly 歌留多 or 加留多) and konpeitō (a confection, commonly 金平糖). The the case of karuta, at least, it feels enough like a regular Japanese word that it undergoes a morphophonological transformation (rendaku e.g. uta-garuta) typically reserved for the native Japanese lexicon (i.e. not Sino-Japanese or other loanwords).