The most common and most likely answer to this crossword clue is the 11 letter word ASSASSINATE
A
S
S
A
S
S
I
N
A
T
E
More clues leading to the result ASSASSINATE
- On account of mouth filling, swallowed ice
- Do in Staines ruined after Wally takes first of amphetamines
- Kill like elite force with crime destroyed
- Murder of two idiots by prisoner – no mark visible
- Two mammals one knight had to kill
- Class as sin a tenet including murder
- Trespass as sin, a term including murder
- Get rid of a couple of fools with one neat manoeuvre
- Top and bottom, sexy, losing head then heart
- Pair of idiots batting, getting knocked back and hit
Buddy explains!

The straight part
We know that "Top" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case top = assassinate.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 ASSASSINATE mean?
ASSASSINATE noun- Assassination, murder.
- An assassin.
- To murder someone, especially an important person, by a sudden or obscure attack, especially for ideological or political reasons.
- To harm, ruin, or defame severely or destroy by treachery, slander, libel, or obscure attack.