IPA: /ˈprɛʃərləs/
KK: /ˈprɛʃərləs/
Not having any force or weight applied to it; free from stress or tension.
The pressureless environment allowed the experiment to proceed without any external influences.
Pressureless → It is formed from "pressure" (from Latin *pressura*, meaning the act of pressing) and "-less" (meaning without). The word "pressureless" means without pressure or free from pressure.
Think of being 'without' ('-less') the act of 'pressing' ('pressure') — that's why pressureless means free from pressure.