Athlete holding nothing back, one that’s in top gear? (8)
Witness maybe attending trial with tankers? (8)
(Perhaps I should give up and do some more weeding)
A six-letter word for a body, having US removed ('left by us') and then being reversed ('returned'), followed by a four-letter word for 'stirring', which involves your three letters. The whole is an archaic word meaning 'prone'.