The most common and most likely answer to this crossword clue is the 2 letter word OH
O
H
Buddy explains!
The straight part
We know that "goodness" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case goodness = oh.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does OH mean?
OH noun- An utterance of oh; a spoken expression of surprise, acknowledgement, etc.
- To utter the interjection oh; to express surprise, etc.
- Expression of surprise.
- Expression of wonder, amazement, or awe.
- Expression of understanding, affirmation, recognition, or realization.
- A word to precede an offhand or annoyed remark.
- A word to precede an added comment or afterthought.
- An invocation or address (similar to the vocative in languages with noun declension), often with a term of endearment.
- Exclamation for drama or emphasis (often poetic).
- Expression of pain. See ouch.
- Space filler or extra syllable, especially in (popular) music.
- (interrogative) Expression of mild scepticism.
- A word to mark a spoken phrase as imaginary.
- The letter O, o (more commonly spelled o)
- The digit 0 (especially in representations of speech)