Journalist consumed by endless lethargy, wreck (7)
I believe the answer is:
torpedo
'wreck' is the definition.
(I've seen this before)
'journalist consumed by endless lethargy' is the wordplay.
'journalist' becomes 'ed' (short for editor).
'consumed by' means one lot of letters goes inside another.
'endless' means to remove the last letter.
'lethargy' becomes 'torpor' (I've seen this before).
'torpor' with its final letter removed is 'torpo'.
'ed' placed within 'torpo' is 'TORPEDO'.
(Other definitions for torpedo that I've seen before include "Self-propelled underwater explosive device" , "Missile fired from underwater submarine" , "Poor Ted (anag)" , "Trooped off with undersea missile" , "ruin" .)