The most common and most likely answer to this crossword clue is the 7 letter word SMACKER
S
M
A
C
K
E
R
Buddy explains!

The straight part
We know that "x (representation of a kiss, or smacker)" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case x (representation of a kiss, or smacker) = smacker.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.
What does SMACKER mean?
SMACKER noun- One who smacks or spanks.
- One who makes a smacking noise, especially while eating.
- A kiss.
- The lips.
- A dollar.
- (usually in the plural) A pound (money).