The most common and most likely answer to this crossword clue is the 7 letter word PEACOCK
I've seen this crossword clue in The Daily Telegraph
P
E
A
C
O
C
K
More clues leading to the result PEACOCK
- Eat sparingly with a company in part of a muster?
- A vain, strutting person, Thomas Love!
- Vain person? Love is my middle name
- Vain person in a heap after PE
- Exercise a fowl to produce a more beautiful bird
- Scoff largely at nonsense in support of Portugal’s winger
- A quick kiss, embracing a firm, gorgeous bird
- Butterfly gives a firm penetrating nip
- Butterfly gives a firm nip on the outside
- Kiss overwhelms a firm, vain fellow
Buddy explains!

The straight part
We know that "Vain character" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vain character = peacock.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 PEACOCK mean?
PEACOCK noun- A male peafowl, especially Pavo cristatus, notable for its brilliant iridescently ocellated tail.
- A peafowl (of the genus Pavo or Afropavo), either male or female.
- A vainglorious person .
- Any of various Asian species of papilionid butterflies of the genus Papilio.
- To strut about proudly.
- To engage in peacocking, ostentatious dress or behaviour to impress women.