Hello

is it possible to add something( like "!", "?" or button) for some words, then the respondents can click to show the definition?
 for example the follwing picture, we can see the definition when we move the arrow to "!"

Thank you very much. 

Where do you want to do this ?
On public survey ?

yes. for example, question: what is your job[!]? when the respondent moves the arrow to [!], they can know the definition of the job.

getbootstrap.com/docs/3.3/javascript/#popovers for example

thank you, i will try it