noun, noun or participle which takes 'suru', intransitive verb
long visit; overstaying
Often used in negative or cautionary contexts, such as 長居する (to stay too long) or 長居は無用 (don't overstay your welcome).
あまり長居すると迷惑になるよ。
If you stay too long, you'll be a bother.
ちょっと長居しすぎた。
I stayed a bit too long.
長話 refers specifically to a long conversation, while 長居 is about staying somewhere for a long time.
Compound of 長 (long) and 居 (stay).