According to Reference.com, "manipulate" means to unfairly manage or influence in a skillful manner, such as "to manipulate people's feelings." It can also reference handling with skill in some type of process, such as "to manipulate a large tractor," without the implication of unfair or nefarious intent.
"Manipulate" also means to change or adapt figures, statistics or accounts to one's advantage. The origin of the word dates back to the early 19th century, and synonyms include "juggle" and "falsify." Related forms include the adverb "manipulatively" and the nouns "manipulation" and "manipulator." An example sentence using "manipulate" is "Most digital cameras come with basic software that helps organize and manipulate photographs."