Powerful transport turning right to start with (9)
I believe the answer is:
Here is my best explanation:
'powerful' is the definition.
'transport turning right to start with' is the wordplay.
'transport' becomes 'enchant' ('enchant' can be a synonym of 'transport'**).
'turning' says the letters should be written backwards.
'right' becomes 'rt'.
'to start with' says to put letters next to each other.
'rt' written backwards gives 'tr'.
'enchant' after 'tr' is 'TRENCHANT'.
(Other definitions for trenchant that I've seen before include "Vigorous and effective", "Showing keenness", "caustic?", "Distinctly defined", "Forthright, vigorous", "Incisive in expression", "Hard-hitting", "Cutting, forthright", "Vigorous, incisive" and "Distinct".)