The most common and most likely answer to this crossword clue is the 9 letter word TRAVAILED
T
R
A
V
A
I
L
E
D
Buddy explains!
The straight part
We know that "worked hard at one time" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case worked hard at one time = travailed.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 TRAVAILED mean?
TRAVAILED verb- To toil.
- To go through the labor of childbirth.