The most common and most likely answer to this crossword clue is the 5 letter word WORKS
W
O
R
K
S
More clues leading to the result WORKS
Buddy explains!

The straight part
We know that "Factory/Acts/the opera" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case factory/acts/the opera = works.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 WORKS mean?
WORKS noun- (heading) Employment.
- (heading) Effort.
- Sustained effort to achieve a goal or result, especially overcoming obstacles.
- (heading) Product; the result of effort.
- The staging of events to appear as real.
- Ore before it is dressed.
- The equipment needed to inject a drug (syringes, needles, swabs etc.)
- To do a specific task by employing physical or mental powers.
- To effect by gradual degrees.
- To embroider with thread.
- To set into action.
- To cause to ferment.
- To ferment.
- To exhaust, by working.
- To shape, form, or improve a material.
- To operate in a certain place, area, or speciality.
- To operate in or through; as, to work the phones.
- To provoke or excite; to influence.
- To use or manipulate to one’s advantage.
- To cause to happen or to occur as a consequence.
- To cause to work.
- To function correctly; to act as intended; to achieve the goal designed for.
- To influence.
- To effect by gradual degrees; as, to work into the earth.
- To move in an agitated manner.
- To behave in a certain way when handled
- (with two objects) To cause (someone) to feel (something); to do unto somebody (something, whether good or bad).
- To hurt; to ache.
- A mechanism or machine; the means by which something happens.
- A factory or factories, or similar collection(s) of buildings.
- (with "the") Everything or everything that is available or possible; especially, all available toppings on food.
- (with "the") Drastic treatment; abuse; the axe (dismissal).