Intrude clumsily lacking experience (7)
I believe the answer is:
untried
'lacking experience' is the definition.
(I've seen this in another clue)
'intrude clumsily' is the wordplay.
'clumsily' is an anagram indicator.
'intrude' anagrammed gives 'UNTRIED'.
(Other definitions for untried that I've seen before include "Not yet experienced" , "Yet to be taken to court" , "inexperienced" , "virgin" , "novel" .)