Chinese grammar: Questions with 呢"ne"
When you use 不怎么 (bù zěnme) before an adjective, it means "not very." This structure is similar to how English speakers may say something is "not very good".
When used together with an adjective, 不怎么 becomes similar to 不太, which means that the degree of the adjective is not very high.
Using this grammar structure is a way to indirectly or mildly state something. Instead of saying "他不太聪明" you can say "他不怎么聪明", turning a very direct statement to a milder, more wayward statement.
这个 人 不怎么 好。
Remember that to make 不怎么 mean "not very" use it with an adjective. Using it with a verb will give it the meaning of "not often."