Synonyms for Increase:

n.

upswing, surge, spurt, explosion, leap. go through the roof, go up, double, accretion, add to. build up, beef up, soar, snowball, proliferate, build, mount, wax, upsurge, rise, run up, aggrandize. propagate, breed, reproduction, spawn, reproduce, procreate. addition (noun)
addition, enlargement, acquisition, augmentation, increment, accumulation, attainment, aggregation, accrual, expansion.
addition, growth (noun)
elaboration, incorporation, escalation, burgeoning, raise, boost, hike, upgrade, augmentation, merger, extension, surge, accrual, inflation, rise, development, enlargement, accumulation, increment, upsurge, accretion, spread, multiplication, swelling, gain, swell, expansion.
augmentation (noun)
swelling, appendix, amalgamation, addendum, adjunct.
duplication (noun)
multiplication.
expansion (noun)
development, burgeoning, spreading, stretching, broadening, distension, engorgement, amplification, lengthening, crescendo, thickening, widening, dilation, fattening.
growing (noun)
developing, increasing.
improvement (noun)
upswing.
increase (noun)
gain, magnification, extension, inflation, step up, elevation, increment, growth, addition, multiplication.
prosperity (noun)
boom.

v.

add (verb)
acquire, sum, annex, tally, add, accumulate, accrue, aggregate, attain, total, augment.
add or grow (verb)
deepen, amplify, advance, lengthen, broaden, enlarge, build up, dilate, augment, double, progress, sharpen, reinforce, inflate, heighten, proliferate, aggrandize, thicken, widen, exaggerate, multiply, escalate, extend, snowball, distend, wax, annex, magnify, step up, develop, mount, expand, intensify, build.
expand (verb)
distend, spread, dilate, engorge, swell, thicken, stretch, develop.
increase (verb)
boost, grow, raise, advance, lengthen, multiply, extend, upgrade, reinforce, inflate, widen, enlarge, elevate, expand, broaden, amplify, fatten, maximize, burgeon.
intensify (verb)
emphasize, beef up, magnify, intensify, exaggerate, deepen, escalate, stress, sharpen, heighten, underline, accentuate.

Other synonyms:

build up, propagate, mount. reproduce, reproduction. accumulation
accretion.
bloom
burgeon.
expand
expand, thicken.
extend
lengthen.
growth
upswing.
improve
upgrade.
intensify
heighten.
open up
widen.
step-up
step up.
strengthen
beef up.

Usage examples for increase

  1. But do not these French turns increase the beauty of your language? – The Memoires of Casanova, Complete The Rare Unabridged London Edition Of 1894, plus An Unpublished Chapter of History, By Arthur Symons by Jacques Casanova de Seingalt
  2. These attractions seldom increase – Across the Zodiac by Percy Greg
  3. Eddie knew just how much money was coming in and there was no temptation to hope for an increase – In a Little Town by Rupert Hughes