The most common and most likely answer to this crossword clue is the 7 letter word STOP-GO
I've seen this crossword clue in The Guardian
S
T
O
P
-
G
O
More clues leading to the result STOP-GO
Buddy explains!

The straight part
We know that "Fitful" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fitful = stop-go.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 STOP-GO mean?
STOP-GO noun- An economic policy of this kind.
- Alternately active and inactive.