Exact meaning of Manual testing is,testing the software or 
any application by manually without use of automation tools.

testing through human observations

Manual testing is the process of manually testing software 
for defects. It requires a tester to play the role of an 
end user, and use most of all features of the application 
to ensure correct behavior. To ensure completeness of 
testing, the tester often follows a written test plan that 
leads them through a set of important test cases.