Recidivist regularly concealed gear under rugby player's top (10)

'recidivist' is the definition.
(synonyms)

'regularly concealed gear under rugby player's top' is the wordplay.
'regularly concealed' indicates alternate letters (letters removed at regular intervals).
'under' is a charade indicator (letters next to each other) (below, in a down clue).
'rugby player's' becomes 'back's' (type of rugby player).
'top' becomes 'lid' (lid is a kind of top).
The alternating letters of 'gear' are 'er'.
'backs'+'lid'='backslid'
'er' after 'backslid' is 'BACKSLIDER'.