Morse deciphered before noon lecture (6)
I believe the answer is:
sermon
'lecture' is the definition.
(I know that sermon is a type of lecture)
'morse deciphered before noon' is the wordplay.
'deciphered' indicates an anagram (I've seen this in other clues).
'before' means one lot of letters go next to another.
'noon' becomes 'n' (abbreviation for noon).
'morse' with letters rearranged gives 'sermo'.
'sermo'+'n'='SERMON'
(Other definitions for sermon that I've seen before include "Pulpit speech" , "Tedious admonition" , "Address of a religious nature" , "Lecture from a pulpit" , "Lesson or religious talk" .)