The /ʌ/ vowel is spelled with <u> and <o> in worry. The /ɪə/ vowel is spelled <ear>, <eer>, or <ier>.
This is a contrast between a short vowel and a diphthong widely separated in the mouth. It does not seem to be a problem for many learners.
The density figure is 0.45%. The set makes 11 semantic contrasts for a loading of 61%.
bud beard budded bearded budding bearding buds beards buzz beers does dears Durham Dereham fuss fierce fuzz fears pus pierce spud speared stud steered unworried unwearied us ears worry weary worried wearied worries wearies worrisome wearisome worrying wearying
John Higgins, Shaftesbury, December 2009