Retweeting someones tweet and leaving out an important part of the original message for your own means or agenda.
Yours is NOT a RT. U completely tweetjacked my message w/UR agenda!
To post tweets in a hashtag thread or stream that are off topic from the intended purpose of a twitter feed. These posts are often purposefully satirical or lewd in nature and are intended to seize attention away from the intended purpose of the topic or stream.
The Twitter feed for the real estate conference I attended was tweetjacked by someone who kept posting information about their least favorite smells.