Self-praise; praising oneself or one's own things (often used modestly as a preface: “pardon my self-praise…”).
手前味噌ですが、うちのサラダは好評です。
Pardon my self-praise, but our salad is popular.
それは手前味噌に聞こえるかもしれないが、彼は本当に優秀だ。
That may sound like self-praise, but he really is excellent.
手前味噌を言うつもりはないが、今回の企画は成功だった。
I don't mean to boast, but this project was a success.