A digger oddly worried (2,4)
I believe the answer is:
on edge
'worried' is the definition.
(I know that worried can be written as on edge)
'a digger oddly' is the wordplay.
'a' becomes 'one'.
'oddly' means one should take alternating letters (letters in the odd-numbered positions are used).
The alternating letters of 'digger' are 'dge'.
'one'+'dge'='ON EDGE'
(Other definitions for on edge that I've seen before include "Apprehensive" , "Tense and irritable, with nerves stretched" , "Highly strung" , "Twitchy" , "Nervously excited" .)