Typical molar rotten? Not initially: that’s how it begins (6)
I believe the answer is:
normal
'typical' is the definition.
(similar in meaning)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for normal that I've seen before include "Ordinary, usual" , "Standard, expected" , "'Usual, typical (6)'" , "'Usual, standard (6)'" , "Common" .)