The most common and most likely answer to this crossword clue is the 7 letter word CHAUCER
I've seen this crossword clue in The Guardian
C
H
A
U
C
E
R
More clues leading to the result CHAUCER
- Opportunist has change of heart, becoming poet
- Wide boy has change of heart, becoming poet
- Middle-aged English travel writer
- Old poet’s writing, say, after seeing two churches lined with gold
- 3 of Pilgrims Progress, opportunist whose heart flipped?
- Poet‘s 18 – it’s said you see the Queen
- Opportunist for all to see supplanting Northern writer
- Poet failing to rewrite cartouche
Buddy explains!
The straight part
We know that "3 of Pilgrims Progress" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case 3 of pilgrims progress = chaucer.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.