An engineering tradeoff is a design choice that improves one property at the expense of another, such as speed versus reliability, or security versus cost. In computing, no system can maximize every goal at once: stronger encryption, more logging, stricter access controls, and redundant hardware all add overhead, complexity, or expense.
This matters in cyber security because attackers often exploit the weak point created by a tradeoff. A team may choose convenience over strict validation, or performance over deep inspection, and that can open paths for phishing, privilege abuse, or data exfiltration. Defenders also use tradeoffs deliberately: rate limits reduce abuse but can frustrate users; segmented networks reduce blast radius but complicate administration. Good security engineering is not about eliminating tradeoffs, but choosing them consciously and documenting the risk.