Singer learning line gutted and truncated it (7)
I believe the answer is:
lorelei
'singer' is the definition.
(I've seen this before)
'learning line gutted and truncated it' is the wordplay.
'learning' becomes 'lore' (both can mean tradition or knowledge).
'gutted' means to remove the middle letters (to gut something is to remove its insides).
'and' means one lot of letters go next to another.
'truncated' means to remove the last letter.
'line' with its centre removed is 'le'.
'it' with its final letter removed is 'i'.
'lore'+'le'+'i'='LORELEI'
(Other definitions for lorelei that I've seen before include "enchantress" , "Dangerous female" , "Great Rock on the Rhine where 37 across lived" , "Rhine Rock where siren lived" , "alluring female" .)