The most common and most likely answer to this crossword clue is the 11 letter word COLOUR-FAST
C
O
L
O
U
R
-
F
A
S
T
Buddy explains!
The straight part
We know that "now unlikely to run" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case now unlikely to run = colour-fast.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 COLOUR-FAST mean?
COLOUR-FAST adjective- Having colors that have been dyed or applied to the material in a way that will prevent them from being washed out, running, or fading.