Even so, it’s somehow extremely logical (5)
I believe the answer is:
still
'even so' is the definition.
(I know that even so can be written as still)
'it's somehow extremely logical' is the wordplay.
'somehow' is an anagram indicator.
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'logical' with its middle taken out is 'll'.
'its' with letters rearranged gives 'sti'.
'sti'+'ll'='STILL'
(Other definitions for still that I've seen before include "Silence" , "in spite of this" , "source of spirits" , "Yet - hushed" , "Static photograph" .)