The most common and most likely answer to this crossword clue is the 7 letter word OVERRUN
I've seen this crossword clue in The Daily Telegraph
O
V
E
R
R
U
N
More clues leading to the result OVERRUN
- Go on too long about catching your vicar gyrating
- Score after six balls exceed allotted time
- Finished? Manage not to finish on time
- Extend beyond time showing cricket terms
- Terms at Old Trafford last longer than planned
- Terms used in cricket are too long
- Go too far in complete control
- Storm to last longer than expected
- Speed too much and exceed limit
- Porn content extended to go beyond agreed limit
Buddy explains!

The straight part
We know that "go on too long" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case go on too long = overrun.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 OVERRUN mean?
OVERRUN noun- An instance of overrunning
- The amount by which something overruns
- Air that is whipped into a frozen dessert to make it easier to serve and eat.
- To defeat an enemy and invade in great numbers, seizing the enemy positions conclusively.
- To infest, swarm over, flow over.
- To run past; to run beyond.
- To continue for too long.
- To carry (some type, a line or column, etc.) backward or forward into an adjacent line or page.
- To go beyond; to extend in part beyond.
- To abuse or oppress, as if by treading upon.