From the deep area near a lake entered by ship (7)
I believe the answer is:
abyssal
'from the deep' is the definition.
(abyssal can mean from an abyss)
'area near a lake entered by ship' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'near' becomes 'by' (near means close by).
'lake' becomes 'L' (geographical abbreviation).
'entered by' is an insertion indicator (I've seen this in other clues).
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'by'+'a'+'l'='byal'
'byal' placed around 'ss' is 'byssal'.
'a'+'byssal'='ABYSSAL'
(Other definitions for abyssal that I've seen before include "regarding ocean trenches?" , "on the bed" , "Bottomless" , "Belonging to ocean depths" .)