The most common and most likely answer to this crossword clue is the 16 letter word BUMPER-TO-BUMPER
I've seen this crossword clue in The Times
B
U
M
P
E
R
-
T
O
-
B
U
M
P
E
R
More clues leading to the result BUMPER-TO-BUMPER
Buddy explains!
The straight part
We know that "almost touching, though not moving?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case almost touching, though not moving? = bumper-to-bumper.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 BUMPER-TO-BUMPER mean?
BUMPER-TO-BUMPER adjective- Very crowded and slow-moving, particularly with regard to motor vehicle traffic.