noun
A casual, often shortened or affectionate name used in place of a person's real name. Common in informal contexts.
彼のニックネームは「タカ」です。
His nickname is 'Taka'.
友達にはニックネームで呼ばれている。
I'm called by my nickname by my friends.
あだ名 is a native Japanese word for nickname, often with a slightly more playful or teasing nuance, while ニックネーム is a direct loan from English and feels more modern and casual.
愛称 specifically refers to a pet name or affectionate nickname, emphasizing endearment rather than just a casual alternative name.
Loanword from English 'nickname', adopted into Japanese with katakana spelling.