Conjoin and Join forces

Conjoin verb - To come together to form a single unit.

Join forces and conjoin are semantically related In some cases you can use "Join forces" instead a verb "Conjoin".

Join forces verb - Work together on a common enterprise or project.

Conjoin and join forces are semantically related in associate topic. Sometimes you can use "Conjoin" instead a verb phrase "Join forces", if it concerns topics such as combine.