Has a saint to speak thus? (7)
I believe the answer is:
stutter
'has a' is the definition.
I can't judge whether this defines the answer.
'saint to speak thus?' is the wordplay.
'saint' becomes 'st' (abbreviation).
'to' is a charade indicator (letters next to each other).
'speak thus?' becomes 'utter' (synonyms. I am not sure about the 'thus?' bit.).
'st'+'utter'='STUTTER'
Can you help me to learn more?
(Other definitions for stutter that I've seen before include "Stumble over words" , "Speech defect in repeating first consonants of words" , "Stammer" , "Struggle to speak" , "s...say?" .)