The answer to what is the baseword to thoughtful is ful...
signify
Swim.
merchand
A baseword is the main part of a word to which prefixes and suffixes can be added to create new words. It is the central meaning or core element of a word before any affixes are attached.
There isn't one.
What is the base word in unseated
The root word is dance.
That would be "strength".
The base word for conclusion is "conclude."
The base word for "disappear" is "appear."
The base word of traditional is "tradition."