WordNet records no synonym and no antonym for time frame. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a time period during which something occurs or is expected to occur
“an agreement can be reached in a reasonably short time frame”
Synonyms, antonyms and the broader and narrower relations for time frame come from Princeton University’s WordNet. Full sources and licences.