9 across
Partially
staunch
a
smoking
fissure
(5)
Partially staunch a smoking fissure (5)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
Look at "fissure" at the end — that's your definition, a deep crack in the ground. Now check "Partially" — that's telling you the answer is hiding inside the words nearby: staunCH A Smoking gives you CHASM tucked away in there.