Cropped up as a ceiling fitment (5)
I believe the answer is:
arose
'cropped up' is the definition.
(I've seen this before)
'a ceiling fitment' is the wordplay.
'ceiling fitment' becomes 'rose' (I can't explain this - if you can you should believe this answer much more).
'a'+'rose'='AROSE'
'as' acts as a link.
Can you help me to learn more?
(Other definitions for arose that I've seen before include "''. ... by any other name would smell as sweet'' (Romeo and Juliet)" , "Issued" , "Came about" , "Originated (from)" , "Emerged from" .)