How to apologize in Japanese

In business, the following formula is used as an excuse: Sumimasen, Mōshiwakearimasen, Shitsureishimasu, Gomennasai. If you are late, for example, because of a transport problem that is not within your responsibility, apologize anyway. Whatever the reason, you have violated your promise... You must first apologize.

• す み ま せ ん Sumimasen

The first term that comes to mind to apologize in Japanese is す み ま せ ん Sumimasen.
You're probably already know this word, but think again, because it contains a lot more meanings than you might think ...

Its etymology is very interesting since the verb which it is drawn, It is the polite negative form of the verb 済 む Sumu. So sumimasen literally means "not finished".
There is also another Sumu verb 澄 む. It means "to clarify". The Sumu of す み ま せ ん is actually a mixture of these two verbs.
One can use "Sumimasen" in many situations. You may hear Japanese say sumimasen receiving a gift, It is particularly used to thank (perhaps as much as ありがとう Arigatō).

• 申し訳ありません Mōshiwakearimasen

申し訳ありません Mōshiwakearimasen is a more polite form of sumimasen. This expression suitable in normal conditions but, in the workplace or to persons of higher rank. Guilt is expressed stronger.
As す み ま せ ん Sumimasen, 申 し 訳 あ り ま せ ん Mōshiwakearimasen can also be used to express his gratitude.

• ご め ん な さ い Gomennasai

ご め ん な さ い Gomennasai replaces sumimasen when one wishes to ask forgiveness after the fact, for example, if you pushed someone or forgotten appointments.
This is a common and familiar expression. It is therefore not used in a formal framework to which we must mark of respect.
Among friends, we can simply use ご め ん Gomen or ご め ん ね Gomenne.

• 失礼 し ま す Shitsureishimasu

In some special situations, we can use rather 失礼 し ま す Shitsureishimasu. It is a formal expression but not as profound as Mōshiwakearimasen.

• The body language of apology in Japan

These expressions are accompanied mostly with bowing.