The most common and most likely answer to this crossword clue is the 5 plus 4 letter word OTHER HALF
I've seen this crossword clue in The Times
O
T
H
E
R
H
A
L
F
More clues leading to the result OTHER HALF
- The Dutch? How differently they live!
- Dutch people better off than us?
- Make an effort to take top off beer for mate
- Old lady that hasn’t married prince needing female consort?
- Trouble and strife, maybe bad for health
- Poor health for partner
- Wife, say, alternatively drinking the small beer
- Partner of entertaining prince following the king
- Short rest then 45 mins of footie, mate?
- Husband or wife has the rest of 9, maybe
Buddy explains!

The straight part
We know that "mate" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case mate = other half.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.