21 across
Zoned
out:
this
is
ignoring
the
writer’s
parts
(8)
Zoned out: this is ignoring the writer’s parts (8)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
parts is your definition here — think fractions or portions of a whole. "Zoned out" signals an anagram of ZONED giving you DOZEN, then "this is ignoring the writer" means take THIS and drop the I (the writer being "I"), leaving THS, and bolt the two together for your answer.