Thrown across line as hymns are (5)
I believe the answer is:
slung
'thrown' is the definition.
'across line as hymns are' is the wordplay.
'across' indicates putting letters inside.
'line' becomes 'l'.
'as hymns are' becomes 'sung'.
'l' inserted into 'sung' is 'SLUNG'.
(Other definitions for slung that I've seen before include "Hurled" , "Threw out" , "Thrown; suspended loosely" .)