Bottle of great importance, lacking central element (4)
I believe the answer is:
vial
'bottle of great importance' is the definition.
'vial' can be an answer for 'bottle' (vial is a kind of bottle). I'm unsure of the 'of great importance' bit.
'lacking central element' is the wordplay.
'lacking central' becomes 'vi' (I can't justify this - if you can you should believe this answer much more).
'element' becomes 'Al' (Al is the chemical symbol for aluminium).
'vi'+'al'='VIAL'
Can you help me to learn more?
(Other definitions for vial that I've seen before include "Small glass container" , "Small bottle used for medicines, laboratory work, etc" , "Ampoule" , "Bottle that contains a drug" , "Small container for liquid medicine" .)