Cryptic crossword clue
Optimistic expectation for catching fish, given decent information 4,4,6

The most common and most likely answer to this crossword clue is the 4 plus 4 plus 6 letter word FEEL GOOD FACTOR

I've seen this crossword clue in Financial Times
F
E
E
L
G
O
O
D
F
A
C
T
O
R

Buddy explains!

The straight part
We know that "Optimistic expectation" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case optimistic expectation = feel good factor.
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.

Latest crossword clues with full explanations