without any others being included or involved
"was entirely to blame"
"a school devoted entirely to the needs of problem children"
"he works for Mr. Smith exclusively"
"did it solely for money"
"the burden of proof rests on the prosecution alone"
"a privilege granted only to him"
Alone; exclusively.
"She decided to solve the problem solely by herself without asking for any help."
In plain English: Solely means doing something for only one specific reason and nothing else.
"The success of the project was solely due to their hard work."
Solely comes from Middle English soly, which was formed by adding the suffix -ly to the word sole. It entered modern usage as an adverb meaning "only" or "alone."