Collins COBUILD Advanced Learner's English Dictionary - uncertain

1. If you are uncertain about something, you do not know what you should do, what is going to happen, or what the truth is about something. He was uncertain about his brother’s intentions... They were uncertain of the total value of the transaction... He stopped, uncertain how to put the question tactfully... With some hesitation and an uncertain smile, she held out her hand. = unsure ? certain ADJ: usu v-link ADJ, oft ADJ about/of n, ADJ wh/that • uncertainly He entered the hallway and stood uncertainly. ADV: usu ADV after v 2. If something is uncertain, it is not known or definite. How far the republics can give practical help, however, is uncertain... It’s uncertain whether they will accept the plan... Students all over the country are facing an uncertain future. ADJ: usu v-link ADJ, oft it v-link ADJ wh 3. If you say that someone tells a person something in no uncertain terms, you are emphasizing that they say it strongly and clearly so that there is no doubt about what they mean. She told him in no uncertain terms to go away. PHRASE: PHR after v c darkgreen]emphasis