Fearthought is a robber.
Forethought is constructive.
Fearthought is destructive.
Forethought suggests the building of houses for shelter wherein there can be no fearthought about storms.
Fearthought fusses and worries over the possibility of not getting the shelter ready in time to protect against inclement weather, and thereby wastes the available energy, and delays the completion of the shelter.
Forethought calmly proceeds to perform a useful task without fearthought of the extent of it. It does all that it can do—it can do no more.
Fearthought wrings its hands, and wastes its time in saying, "How can I ever do it?"
There is no difficulty in determining between forethought and fearthought.