self-preservation first; looking out for oneself above all
Describes a mindset or behavior where protecting one's own interests, safety, or position is the top priority, often with a negative connotation of selfishness or lack of concern for others.
He always puts self-preservation first and doesn't think about others.
Voters were disappointed by the politician's self-serving attitude.
自己保身 is a more formal, compound noun meaning 'self-protection' or 'self-preservation', while 保身第一 is a set phrase emphasizing that self-protection is the top priority.
身を守る is a verb phrase meaning 'to protect oneself' in a physical or defensive sense, whereas 保身第一 is a noun/expression describing a self-centered attitude.
Compound of 保身 (self-protection) and 第一 (first, foremost). The exact historical derivation is uncertain, but the phrase is used in modern Japanese to describe a self-serving attitude.