this is not an elaborated explanation of the terms constructivism but it is more a clarification of the term that nowadays bifurcates in two.
from one side we have
the Social Constructivists that support the view that reality is always social mediated and mind-dependent and
Radical contructivists that argue that mind-independent entities exist and they are knowable.
thus
[Social] Constructivism is concerned with the social construction of reality
[Radical] Constructivism is concerned with the construction of reality
however it will be really dangerous to support that view that the social reality is mind independent
Manuel Delanda will clarify this point: "in the case of social ontology though this definition (of mind independence) must be qualified because most of the social entities, would disappear althogether if human minds cease to exist. In this sense social entities are clearly not mind independent but [as he adds later] the reality is conception-independent" (Deland 2006, p1)