These two words are hyphenated in the dictionary as adjectives and adverbs. However, as we know, the adjective form in the dictionary is the direct adjective form, i.e., the form right in front of the noun. Predicate and appositive adjectives are not hyphenated.
So they are hyphenated as direct adjectives
and as adverbs
…He works full-time.
…We were with him only part-time.
but not as predicate adjectives.
…His job is full time.
…It is only part time.