Word: welleth
Part of speech: Verb
Syllables: we
lleth
Definition: Third-person singular of well; thoroughly or completely; fully; often used as a combining form; 
Morphemes:
Affix: well
Language: en
PoS: Adverb
Meaning: Completely, fully.
Affix: -eth
Language: en
PoS: Suffix
Meaning: Used to form the third-person singular present indicative of verbs.