I've designed this myself and I want to know whether my answer is correct and if there are any more possible answers.
Which is the odd one out?
$$\large\text{courtesy, bird, hurdle, learn}$$
Answer:
It is hurdle since it is the only one whose first syllable follows its usual pronunciation (ur). For example, courtesy vs our, bird vs wind and learn vs ear have different pronunciations.
Are there any other possible answers to this?