General Antonyms:
* Surmountable: This is the most direct opposite, meaning capable of being overcome.
* Overcomeable: Similar to surmountable, meaning able to be defeated or conquered.
* Manageable: This suggests that the challenge is within control and can be handled effectively.
* Conquerable: This emphasizes the possibility of victory over the obstacle.
More Specific Antonyms:
* Easy: This implies that the challenge is simple and requires little effort.
* Trivial: This suggests that the challenge is insignificant and not worth considering.
* Doable: This implies that the challenge is achievable and within reach.
Other Options:
* Feasible: This indicates that the challenge is practical and likely to succeed.
* Possible: This emphasizes that the challenge is not impossible, even if it might be difficult.
The best antonym for insurmountable depends on the specific situation and the intended meaning.