忙しいのに

even though [someone] is busy

→ 忙しい
phrase Rare #32,324
even though [someone] is busy 忙しいのに combines 忙しい (busy) with のに (even though; despite). The subject is often understood from context. It can also be used with past tense, as in 忙しかったのに (even though [someone] was busy).
JA: 忙しいのに手伝ってくれてありがとう。
EN: Thank you for helping me even though you’re busy.

忙しいのにもうええ

Even though you're busy, it’s okay now.

— 東京物語 (1953)

忙しいのに来てくれて脚本が気に入った

Thanks for coming even though you’re busy. I liked the script.

— マルホランド・ドライブ (2001)

仕事忙しいのに聞いてくれてありがとう

Thank you for listening even though you’re busy with work.

忙しいのにありがとう

Thanks, even though you're busy.

この忙しいのに

Even though you're this busy.

— グッバイ、レーニン! (2003)