Learner in panic beginning to turn red (7)
I believe the answer is:
scarlet
'red' is the definition.
(I know that red can be written as scarlet)
'learner in panic beginning to turn' is the wordplay.
'learner' becomes 'l' (as in a learner driver with L-plates on their car).
'in' means one lot of letters goes inside another.
'panic' becomes 'scare' (synonyms).
'beginning to' says to take the initial letters.
The initial letter of 'turn' is 't'.
'l' going inside 'scare' is 'scarle'.
'scarle'+'t'='SCARLET'
(Other definitions for scarlet that I've seen before include "bloody?" , "Vivid red" , "Cherry-red" , "Fallen" , "Brilliant red colour" .)