Definitions for ugh
Random House Webster's College Dictionary
(used as an exclamation of disgust, aversion, horror, or the like.)
(n.)the sound of a cough, grunt, or the like.
Origin of ugh:
Kernerman English Learner's Dictionary
indicates disgust or annoyance
More hot humid weather? Ugh.
Used to express repugnance, disgust, boredom, annoyance, tiredness, or horror.
When I saw how the stuff in the larder had gone moldy all I could think of to say was, "Ugh"
an exclamation expressive of disgust, horror, or recoil. Its utterance is usually accompanied by a shudder