Antonyms for the phrase "being forthcoming" would include terms such as evasive, secretive, uncommunicative, and guarded. These antonyms denote a reluctance to openly communicate or disclose information, often resulting in a lack of transparency in one's actions or intentions. Being evasive implies dodging questions or inquiries, while being secretive suggests intentionally keeping information hidden. Uncommunicative signifies a lack of willingness to share or participate in communication, and being guarded means being reserved or cautious in the information one reveals. Overall, these antonyms for "being forthcoming" indicate an unwillingness to openly share information, which can lead to misunderstandings and mistrust.