Monosyllabic refers to using words with only one syllable, for example, yes or no. Rarely is the monosyllabic approach appropriate in interviews unless your interviewer specifies that they want a yes or no answer. However, on occasion, some interviewees may freeze in an interview situation and as a result they may mumble monosyllabic answers. Others are comfortable in an interview situation, there may be an element of shyness involved or occasionally some people are just plain rude and prefer to give terse and blunt answers.
Some interviewers may interpret this terseness as pure grumpiness and negativity, which will rarely stand to you in an interview situation. The interviewer may even feel uncomfortable and even consider the interview as painful, not a good image you want to portray as a potential employee.
If you are completely flummoxed by a question, a good tip is to simply repeat the question asked and use the STAR technique to illustrate your answer. STAR refers to Situation, Task, Action and Result. The key is to avoid a monosyllabic answer at all costs unless on a rare occasion you are specifically requested to give “Yes” or “No” answer.