Bright person first to search grassland (5)

I believe the answer is:

spark

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'bright person' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.

'first to search grassland' is the wordplay.
'first to' indicates taking the first letters.
'grassland' becomes 'park'.
The first letter of 'search' is 's'.
's'+'park'='SPARK'

Can you help me to learn more?

(Other definitions for spark that I've seen before include "Bright flash; ignite" , "Glowing particle" , "Flicker -- provoke" , "bit of fire?" , "Particle of fire" .)

I've seen this clue in The Sun.

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