The most common and most likely answer to this crossword clue is the 6 letter word EXCEED
I've seen this crossword clue in The Sunday Telegraph
E
X
C
E
E
D
More clues leading to the result EXCEED
- Pass old germ orally?
- Better, except when editor’s replacing short part
- Outdo formerly ranked player, say?
- Outmatch former top tennis player, say
- Top business chief meets top guy at press, the former turning tail
- Outdo former journalist describing church
- Go one better than old lover with offspring, as you may say
- Overtake roughly in British river, lapping over another going north
- Top or formerly highly-rated player, we hear
- Surpass the has-been tennis player, by the sound of it?
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 = exceed.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 EXCEED mean?
EXCEED verb- To be larger, greater than (something).
- To be better than (something).
- To go beyond (some limit); to surpass; to be longer than.
- To predominate.
- To go too far; to be excessive.