あいにく

あいにく、今日きょうは都合つごうが悪わるい。

ainiku, kyou wa tsugou ga warui.

Unfortunately, today doesn't work for me. neutral

担当たんとうの者ものは、あいにく本日ほんじつ休やすみをいただいております。

tantou no mono wa, ainiku honjitsu yasumi o itadaite orimasu.

I'm afraid the person in charge is off today. formal

Same meaning

• 残念ざんねんながら

  both mean "unfortunately"