Painless means causing no pain or trouble. A painless procedure, completely painless, a painless process.
Of a medical procedure it is a promise made rather more often than it is kept. Of a process it means easy and untroublesome: the whole thing was painless — which is high praise for anything administrative. Note that painless is far commoner in advertising than in description; and that pain-free is the near equivalent and is used more in medicine, where painless describes the procedure and pain-free the patient.
1adjectivepainlessCausing no pain or trouble.
“The injection was quick and almost painless.”
synonyms: pain-free, easy
painless is a quality of causing no pain.
The word is pain plus -less. Pain comes from Latin poena, a penalty, so painless literally means without penalty — which is an unexpectedly legal origin for a medical promise.
Middle English
paynles
English, today
painless
From Middle English paynles, peynlees, equivalent to pain + -less. Compare West Frisian pynleas (“painless”), Dutch pijnloos (“painless”).
Etymology from Wiktionary, CC BY-SA