The most common and most likely answer to this crossword clue is the 5 letter word SERIF
I've seen this crossword clue in Financial Times
S
E
R
I
F
More clues leading to the result SERIF
- Line of text shoots up
- Sacks returned for final part of letters
- Something added to letter gets animated backing
- Addition to letter shoots back
- Slave branded by one, the mark of a printer
- Part of letter inflames revolutionary
- Just one line from a letter
- Dismisses, upon reflection, line added to letter
- Character’s decorative foot brings passions back
- Stroke shoots up
Buddy explains!

The straight part
We know that "Part of letter" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case part of letter = serif.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 SERIF mean?
SERIF noun- A short line added to the end of a stroke in traditional typefaces, such as Times New Roman.
- Of a typeface, provided with serifs.