Fellow one met at church in tight garment (6)
I believe the answer is:
bodice
'tight garment' is the definition.
'fellow one met at church' is the wordplay.
'fellow' becomes 'bod' (I've seen this in other clues).
'one' becomes 'i' (Roman numeral).
'met' says to put letters next to each other.
'at' means one lot of letters go next to another.
'church' becomes 'ce' (abbreviation for Church of England).
'bod'+'i'+'ce'='BODICE'
'in' acts as a link.
(Other definitions for bodice that I've seen before include "Historical novel with lots of passion" , "Upper part of female dress, shoulder to waist" , "Corset" , "Upperpart of woman's dress" , "Garment" .)