Meagre sputtering summer period? (6)

I believe the answer is:

jejune

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'meagre' is the definition.
Both the definition and answer are adjectives. Maybe they are linked in a way I don't understand?

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for jejune that I've seen before include "Naive, immature" , "Barren, dull, unnourishing" , "Naive, simplistic" , "Puerile" , "Scanty or unsatisfying to the mind" .)

I've seen this clue in The Sunday Times and The Times.

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