The most common and most likely answer to this crossword clue is the 8 letter word BROADENS
I've seen this crossword clue in The Daily Telegraph
B
R
O
A
D
E
N
S
More clues leading to the result BROADENS
Buddy explains!

The straight part
We know that "gets wider" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gets wider = broadens.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 BROADENS mean?
BROADENS verb- To make broad or broader.
- To become broad or broader.