Blubber that is enveloping bloke nearly producing lethargy (7)
I believe the answer is:
fatigue
'lethargy' is the definition.
(thesaurus)
'blubber that is enveloping bloke nearly' is the wordplay.
'blubber' becomes 'fat' ('fat' can be similar in meaning to 'blubber').
'that is' becomes 'ie' ('i.e.' can be a synonym of 'that is').
'enveloping' is an insertion indicator.
'bloke' becomes 'guy' (I've seen this before).
'nearly' means to remove the last letter.
'guy' with its last letter taken off is 'gu'.
'ie' placed around 'gu' is 'igue'.
'fat'+'igue'='FATIGUE'
'producing' is the link.
(Other definitions for fatigue that I've seen before include "weary" , "listlessness" , "Weariness, exhaustion" , "Temporary loss of strength and energy" , "military chore" .)