Green’s Dictionary of Slang

my oath! excl.

[mid-19C+] (Aus./N.Z.) a mild excl.; often as an affirmation; often intensified with an adj.

In exclamations

my bloody oath! (also blood oath! bloody oath!)

[mid-19C+] (Aus.) a mild excl.

my colonial oath! (also my colonial!)

[mid-19C+] (Aus./N.Z.) a mild excl.

my fucking oath! (also my ’king oath! fucking oath! kern oath! kin oath!)

[1910s+] (Aus.) a mild excl.