Refers to conflict, power struggles, or factional disputes within an organization, group, or country.
Infighting within the party is intensifying.
I got caught up in the company's internal power struggle.
内紛 is similar but often implies a more open or disruptive internal dispute, while 内部闘争 is a broader term for any internal struggle.
内輪もめ is a more colloquial term for family or small-group squabbling, whereas 内部闘争 is used for formal or organizational conflicts.
Compound of 内部 (internal) and 闘争 (struggle, fight).