The most common and most likely answer to this crossword clue is the 7 letter word REGRESS
I've seen this crossword clue in The Times
R
E
G
R
E
S
S
More clues leading to the result REGRESS
- Move backwards, using right exit
- Go back on sailing vessel on river, say
- Go backwards, and initially reach way out
- Go back coming from right way out
- Fall back drunk, having swapped hands twice
- Right means of escape in retreat
- Go back through right exit
- Go back? That’s the right way out!
- To retire may be the right way out
- Note changes in passionate female making return to former state
Buddy explains!

The straight part
We know that "Fall back" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fall back = regress.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 REGRESS mean?
REGRESS noun- The act of passing back; passage back; return; retrogression.
- The power or liberty of passing back.
- In property law, the right of a person (such as a lessee) to return to a property.
- To move backwards to an earlier stage; to devolve.
- To move from east to west.
- To perform a regression on an explanatory variable.