The most common and most likely answer to this crossword clue is the 5 letter word FLANK
I've seen this crossword clue in Independent
F
L
A
N
K
Buddy explains!
The straight part
We know that "27" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case 27 = flank.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 FLANK mean?
FLANK noun- The flesh between the last rib and the hip; the side.
- A cut of meat from the flank of an animal.
- The extreme left or right edge of a military formation, army etc.
- The sides of a bastion perpendicular to the wall from which the bastion projects.
- The side of something, in general senses.
- The outermost strip of a road.
- The wing, one side of the pitch.
- That part of the acting surface of a gear wheel tooth that lies within the pitch line.
- To attack the flank(s) of.
- To defend the flank(s) of.
- To place to the side(s) of.
- To be placed to the side(s) of something (usually in terms of two objects, one on each side).
- (of speed) Maximum. Historically faster than full speed (the most a vessel can sustain without excessive engine wear or risk of damage), now frequently used interchangeably. Typically used in an emergency or during an attack.