Lycra, deployed originally in cycling material (7)
I believe the answer is:
acrylic
'material' is the definition.
(acrylic is a kind of material)
'lycra deployed originally in cycling' is the wordplay.
'deployed' indicates an anagram.
'originally' says to take the initial letters.
The first letters of 'in cycling' is 'ic'.
'lycra' with letters rearranged gives 'acryl'.
'acryl'+'ic'='ACRYLIC'
(Other definitions for acrylic that I've seen before include "Pungent acid" , "Kind of paint" , "Synthetic resin or fibre used for textiles" , "Shiny paint" , "Textile fibre - icy Carl (anag)" .)