Free from complication or pain: a painless operation. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "painless" in a sentence
"It is also quite a handy trait to have because it makes starting up again quick and painless (well, mostly painless the volcano is a bit sensitive after it erupts)."
"The word "painless" is important: the idea of euthanasia began gaining ground in modern times not because of new technologies for agonizingly prolonging life but because of the discovery of new drugs, such as morphine and various anesthetics for the relief of pain, that could also painlessly induce death."
"In our example, putting custom configuration into the/etc/apache2/conf. d directory results in painless upgrade and fully operational apache after upgrade."