my apologies; I'm sorry; excuse me
A polite, somewhat formal apology phrase. The をば is an emphatic object marker, giving a slightly old-fashioned or deliberate tone. Often used in business or formal settings.
See also: 失礼しました
ご迷惑をおかけして、失礼をばいたしました。
I apologize for causing you trouble.
失礼をば承知で申し上げますが、その計画には無
I say this knowing it may be impolite, but I believe that plan is unreasonable.
A fixed phrase combining 失礼 (rudeness, impoliteness) with the emphatic object marker をば, which is a classical Japanese construction (を + は). The expression literally means 'as for the rudeness' and is used to preface or acknowledge an impolite act.