The most common and most likely answer to this crossword clue is the 5 plus 3 plus 7 letter word DAVID AND GOLIATH
I've seen this crossword clue in The Daily Telegraph
D
A
V
I
D
A
N
D
G
O
L
I
A
T
H
More clues leading to the result DAVID AND GOLIATH
- Biblical combatants who stood within a stone’s throw of each other?
- Poor lad, avoiding death, with no energy for such a fight
- Unequal combat when six intercept father on leave in unstable Thailand
- Vital I’d had gonad treated; in this case a sling helped
- Biblical tale roughly: lad did endless havoc with giant
Buddy explains!
The straight part
We know that "such a fight" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case such a fight = david and goliath.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.