This is the 7679th most frequent Polish word.
lu
The Polish word "lu" is informal slang and can mean "ease," "chill," or "relax."
In this sentence, 'luźny' (related to 'lu') means loose or casual, describing the nature of the plan.
Mamy luźny plan na weekend.
We have a casual plan for the weekend.
The word 'luźna' (from 'lu') here describes a relaxed and informal atmosphere.
Luźna atmosfera sprzyja kreatywności.
A relaxed atmosphere fosters creativity.
Here, 'luźny' (from 'lu') is used in an imperative context suggesting to avoid being overly relaxed.