WordPress already has search capability build-in. It is not the smartest search solution around though. Not when you can use plugins KAIMBO Semantic Search to make searching through content easier for your visitors. KAIMBO Semantic Search is a plugin that goes beyond keyword search and lets users search for related concepts and similar words on your website.
KAIMBO lets you improve your search engine to make it easier for your visitors to look up what they need on your website. The free version does have some limitations. The personal and professional versions offer PDF indexing, concept highlighting, auto-completion, and advanced keywords search. The more advanced plans offer even more search capabilities.
KAIMBO is still in beta. If you are not happy with the default WordPress search, you may want to give this plugin a look.