The most common and most likely answer to this crossword clue is the 6 plus 8 letter word UPHILL STRUGGLE
U
P
H
I
L
L
S
T
R
U
G
G
L
E
Buddy explains!
The straight part
We know that "A hard task" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a hard task = uphill struggle.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.