The most common and most likely answer to this crossword clue is the 8 letter word PARALLEL
I've seen this crossword clue in The Sunday Telegraph
P
A
R
A
L
L
E
L
More clues leading to the result PARALLEL
- Friend coming across artist, Lely, almost exact likeness
- Resemblance completely captured in clip before closure of channel
- Meeting in such bars should be impossible
- In correspondence, mean each and every reply? Oddly not
- English used in a few lines and a few more for comparison
- Matching degree course
- Like to jump up without slowing down
- Corresponding with latitude
- Correspond with mate about keeping everyone in
- Unable to meet standard, female’s sent back by lecturer at first
Buddy explains!

The straight part
We know that "Maintaining distance apart" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case maintaining distance apart = parallel.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 PARALLEL mean?
PARALLEL noun- One of a set of parallel lines.
- Direction conformable to that of another line.
- A line of latitude.
- An arrangement of electrical components such that a current flows along two or more paths; see in parallel.
- Something identical or similar in essential respects.
- A comparison made; elaborate tracing of similarity.
- One of a series of long trenches constructed before a besieged fortress, by the besieging force, as a cover for troops supporting the attacking batteries. They are roughly parallel to the line of outer defenses of the fortress.
- A character consisting of two parallel vertical lines, used in the text to direct attention to a similarly marked note in the margin or at the foot of a page.
- To construct or place something parallel to something else.
- Of a path etc: To be parallel to something else.
- Of a process etc: To be analogous to something else.
- To compare or liken something to something else.
- To make to conform to something else in character, motive, aim, etc.
- To equal; to match; to correspond to.
- To produce or adduce as a parallel.
- Equally distant from one another at all points.
- Having the same overall direction; the comparison is indicated with "to".
- (hyperbolic geometry, said of a pair of lines) Either not intersecting, or coinciding.
- Involving the processing of multiple tasks at the same time.
- With a parallel relationship.