Google AdWords will do this automatically, but only if you enable auto-tagging in your AdWords account.
The best way to do it is to link your Google Analytics account to your AdWords account. By linking the accounts it will automatically enable auto-tagging in AdWords if it isn’t already enabled. In doing so, you will get data from Google Analytics flowing back into your AdWords account making it even easier to optimize your campaign performance using automated scripts.
Google Analytics and AdWords not only give you an overall idea, but they also give you the exact search terms, no 3rd party tools required.
You can disable auto-tagging, or change settings in Google Analytics to allow overriding the auto-tagging if you really need that option for some special purpose.
However, keep in mind that manual tagging does not capture search terms, only the keywords that triggered the ads. If you want to capture search terms, you need to keep the auto-tagging feature enabled and use the “allow auto-tagging override” feature to get all the data including search terms.