The word "frightfully," over and over again (3-3)
I believe the answer is:
too-too
'the word frightfully' is the definition.
I can't judge whether this definition defines the answer.
'over and over again' is the wordplay.
I cannot really see how this works, but
'over' could be 'too' (I've seen this before) and 'too' is present in the answer.
'and' could be 'too' and 'too' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for too-too that I've seen before include "Excessive" , "Excessively (colloq.)" .)