Loud warning about Tesla (5)
I believe the answer is:
forte
'loud' is the definition.
(similar in meaning)
'warning about tesla' is the wordplay.
'warning' becomes 'fore' (shouted in golf).
'about' indicates putting letters inside.
'tesla' becomes 'T' (scientific unit).
'fore' going around 't' is 'FORTE'.
(Other definitions for forte that I've seen before include "A thing in which someone excels" , "speciality" , "Musically, loud" , "Skill" , "sort of musical passage" .)