Tongue-tied without lecture (10)
I believe the answer is:
speechless
I believe this is a double definition.
'tongue-tied' is the first definition.
(thesaurus)
'without lecture' is the second definition.
('lecture' can be 'speech' (synonyms) so maybe 'without lecture' can be ''speechless')
(Other definitions for speechless that I've seen before include "being forced to improvise?" , "Unable to say anything" , "In shock" , "Dumbfounded" , "Struck dumb" .)