Thesaurus.com
Dictionary.com
Definitions

prolong

[pruh-lawng, -long] / prəˈlɔŋ, -ˈlɒŋ /
VERB
extend, draw out
Synonyms
STRONGEST
continue delay drag out lengthen perpetuate protract stall
STRONG
hold increase pad stretch
WEAK
carry on drag one's feet hold up let it ride make longer spin out stretch out
Antonyms
STRONGEST
abbreviate advance cease expedite further halt shorten stop

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.