Strangely not even lazy on vacation (5)
I believe the answer is:
oddly
'strangely' is the definition.
(I know that strangely can be written as oddly)
'not even lazy on vacation' is the wordplay.
'not even' becomes 'odd' ('odd' is the opposite to 'even').
'on vacation' means to remove the middle letters (after the inside letters have vacated the word).
'lazy' with its middle taken out is 'ly'.
'odd'+'ly'='ODDLY'
(Other definitions for oddly that I've seen before include "Strangely, curiously" , "strange to say?" , "Unusually" , "In a peculiar way" , "In a strange way" .)