Wandering in and out of base (10)
I believe the answer is:
foundation
'base' is the definition.
(I know that base can be written as foundation)
'wandering in and out of' is the wordplay.
'wandering' indicates an anagram.
'in'+'and'+'out'+'of'='inandoutof'
'inandoutof' is an anagram of 'FOUNDATION'.
(Other definitions for foundation that I've seen before include "cosmetic aid?" , "Base" , "Artificial jet of water" , "Underlying basis" , "Groundwork, basis" .)