The most common and most likely answer to this crossword clue is the 4 letter word VAMP
I've seen this crossword clue in The Guardian
V
A
M
P
More clues leading to the result VAMP
- Very basic electrical unit for siren
- See member with a seductive woman
- Siren has volume and means to raise it
- Sucker lacking passion and someone to seduce him?
- Provide fill-in music's volume with sound equipment
- Units of electric potential and current in siren
- Volume on speaker for siren
- A femme fatale against a politician
- Five in the morning with quiet attractive girl
- A politician overcome by very seductive woman
Buddy explains!

The straight part
We know that "siren" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case siren = vamp.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 VAMP mean?
VAMP noun- The top part of a boot or shoe, above the sole and welt and in front of the ankle seam, that covers the instep and toes; the front part of an upper; the analogous part of a stocking.
- Something added to give an old thing a new appearance.
- Something patched up, pieced together, improvised, or refurbished.
- A repeated and often improvised accompaniment, usually consisting of one or two measures, often a single chord or simple chord progression, repeated as necessary, for example, to accommodate dialogue or to anticipate the entrance of a soloist.
- (by extension) An activity or speech intended to fill or stall for time.
- To patch, repair, or refurbish.
- Often as vamp up: to fabricate or put together (something) from existing material, or by adding new material to something existing.
- To cobble together, to extemporize, to improvise.
- (shoemaking) To attach a vamp (to footwear).
- To travel by foot; to walk.
- To delay or stall for time, as for an audience.
- A flirtatious, seductive woman, especially one who exploits men by using their sexual desire for her.
- A vampire.
- To seduce or exploit someone.
- A volunteer firefighter.