Hot left back in charge of a learner (8)
I believe the answer is:
tropical
'hot' is the definition.
(similar in meaning)
'left back in charge of a learner' is the wordplay.
'left' becomes 'port' (left side of a ship - opposite of starboard).
'back' says the letters should be written in reverse.
'in charge of' becomes 'ic'.
'learner' becomes 'l' (as in a learner driver with L-plates on their car).
'port' backwards is 'trop'.
'trop'+'ic'+'a'+'l'='TROPICAL'
(Other definitions for tropical that I've seen before include "Boiling" , "Of regions north and south of the Equator" , "Relating to hot and humid parts" , "Found in Cancer or Capricorn" , "rainforest areas" .)