Eccentric got there simultaneously (8)
I believe the answer is:
together
'simultaneously' is the definition.
(I've seen this in another clue)
'eccentric got there' is the wordplay.
'eccentric' is an anagram indicator.
'got'+'there'='gotthere'
'gotthere' with letters rearranged gives 'TOGETHER'.
(Other definitions for together that I've seen before include "Married" , "One with another, simultaneously" , "In each other's company" , "self-confidence" , "Well-controlled" .)