can we change the default shown text on dropdown in qualtrics eg "Select one" to "Unselected"

Hi,

You could try something like this and adapt if you have multiple languages.

Qualtrics.SurveyEngine.addOnReady(function () {

    var spans = document.querySelectorAll('#question-' + this.questionId + ' span.rich-text');

    spans.forEach(function (span) {
        if (span.textContent.trim() === 'Select one') {
            span.textContent = 'Unselected';
        }
    });
});