Rocky7, not sure if this will help, but every themed clue comprises wordplay, giving the clue structure, plus a definition of the thematic word. So for T you have the five letter reversal plus the letter for Rex, and the last word is the (loose) definition. If you look up the thematic words in an appropriate place, you should find their meanings. Here is one such (URL changed to avoid spoiler)
https://tinyurl.com/yck722r6