Hurry to get flimsy source of illumination (9)
I believe the answer is:
rushlight
'source of illumination' is the definition.
(rushlight is a kind of source of illumination)
'hurry to get flimsy' is the wordplay.
'hurry' becomes 'rush' (synonyms).
'to get' means one lot of letters go next to another.
'flimsy' becomes 'light' (I've seen this before).
'rush'+'light'='RUSHLIGHT'
(Other definitions for rushlight that I've seen before include "One that's wicked" , "old candle" .)