Extension synonyms such as delay, add-on, amplification, continuation, and deferral. Extension is a noun, and its antonyms are retrogression and regression. Additionally, here are 44 synonyms, related words, and verbs for extension.
add-on, addendum, addition, adjunct, annexe, appendage, appendix, augmentation, ell, supplement, supplementary building, and wing.
amplification, augmentation, broadening, continuation, deepening, development, diversification, drawing out, elongation, enhancement, enlargement, expansion, growth, heightening, increase, lengthening, stretching, and widening.
additional time, continuation, deferral, delay, increase, increased time, lengthening, longer period, more/extra time, perpetuation, postponement, prolongation, and protraction.