Bhagavad Gita, Chapter 18, Verse 2

The Deity said: The renunciation of Kâmya actions, the sages understand as Sannyâsa: the wise declare the abandonment of the fruits of all works as Tyâga.

Krishna answers with two real, distinct definitions here, not one word standing in for the other.

Giving up desire-driven action and giving up attachment to results are named as genuinely separate things. Real precision in language matters before the deeper teaching can proceed.