Shiny silver coat of ladylike American (6)
I believe the answer is:
agleam
'shiny' is the definition.
(agleam means gleaning or shining)
'silver coat of ladylike american' is the wordplay.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'coat of' means to remove the middle letters (only the letters that coat the word).
'american' becomes 'Am' (abbreviation in some contexts).
'ladylike' with its centre removed is 'le'.
'ag'+'le'+'am'='AGLEAM'
(Other definitions for agleam that I've seen before include "Bright" , "Shining brightly" , "Sparkling" , "scintillating" .)