The most common and most likely answer to this crossword clue is the 6 letter word DOBBIN
I've seen this crossword clue in The Times
D
O
B
B
I
N
More clues leading to the result DOBBIN
Buddy explains!
The straight part
We know that "a workhorse" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a workhorse = dobbin.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 DOBBIN mean?
DOBBIN noun- An old jaded horse.
- Sea gravel mixed with sand.
- Any of several animals related to Equus ferus caballus.
- Equipment with legs.
- Type of equipment.
- A mass of earthy matter, or rock of the same character as the wall rock, occurring in the course of a vein, as of coal or ore; hence, to take horse (said of a vein) is to divide into branches for a distance.
- The sedative, antidepressant, and anxiolytic drug morphine, chiefly when used illicitly.
- An informal variant of basketball in which players match shots made by their opponent(s), each miss adding a letter to the word "horse", with 5 misses spelling the whole word and eliminating a player, until only the winner is left. Also HORSE, H-O-R-S-E or H.O.R.S.E. (see Variations of basketball#H-O-R-S-E).
- (among students) A translation or other illegitimate aid in study or examination.
- (among students) horseplay; tomfoolery
- Heroin (drug).