しつれいしました (かん)
しつれいしました (かん) · shitsureishimashita (kan) · JLPT N2 · noun
maine
失礼 = 失 (lose) + 礼 (courtesy): you lost your manners, so you apologise
失礼 is a noun for rudeness, built from 失 (lose) and 礼 (courtesy). します makes it a polite verb, so しました means 'I did rudeness', said to apologise. Ending it with かん adds an 'Excuse me' tone.