Gruesome sailor runs into club (7)
I believe the answer is:
macabre
'gruesome' is the definition.
(both can mean morbid or disturbing)
'sailor runs into club' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'runs' becomes 'r' (cricket abbreviation).
'into' is an insertion indicator.
'club' becomes 'mace' (mace can mean a club or stick).
'ab'+'r'='abr'
'abr' inserted inside 'mace' is 'MACABRE'.
(Other definitions for macabre that I've seen before include "'Grim, repellent (7)'" , "Morbidly repellent" , "Chilling" , "Ghostly appearance" , "'Grisly, gruesome (7)'" .)