Cryptic crossword clue
Girl they upset having expended energy, for good reason 7

The most common and most likely answer to this crossword clue is the 7 letter word RIGHTLY

I've seen this crossword clue in Financial Times
R
I
G
H
T
L
Y

Buddy explains!

The straight part
We know that "for good reason" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case for good reason = rightly.
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 RIGHTLY mean?

RIGHTLY adverb
  1. In a right manner, correctly, justifiably.

Latest crossword clues with full explanations