The most common and most likely answer to this crossword clue is the 9 letter word TRAVERSAL
I've seen this crossword clue in Independent
T
R
A
V
E
R
S
A
L
More clues leading to the result TRAVERSAL
- Passage that spans short story about uninhibited people
- Crossing finally over, with maniac on board
- Crossing a line in pursuit of writer of farces
- In tent, ravers all find trip over
- Minister turned amidst various altars, making motion to cross
- Test says to replace current crossing
- Crossing a line behind dramatist
- Republican state stops erection of final crossing
- Weekend warriors surround wild party members at front of level crossing
- Crossing Republic of South Africa, journey around
Buddy explains!
The straight part
We know that "motion to cross" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case motion to cross = traversal.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.