noun
outside a gate; beyond one's expertise
Literally 'outside the gate'; figuratively, refers to something outside one's field of knowledge or experience. Often used in the phrase 門外漢 (もんがいかん) meaning 'layman' or 'outsider'.
門外で待っていてください。
Please wait outside the gate.
その話題は私には門外だ。
That topic is outside my area of expertise.