The most common and most likely answer to this crossword clue is the 3 plus 7 plus 4 letter word THE WEAKEST LINK
I've seen this crossword clue in Independent
T
H
E
W
E
A
K
E
S
T
L
I
N
K
Buddy explains!
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.