| improvement(noun, change, advance, increase, progress) |
| lengthening(noun, increase, delay, development, spread) |
| raising(noun, advance, increase, development, boost) |
| spreading(noun, advance, increase, progress, development) |
| strengthening(noun, increase, rise, development, growth) |
| stretching(noun, advance, increase, delay, progress) |
| up(noun, advance, increase, gain, rise) |
| upsurge(noun, act, advance, increase, raise) |
| access(noun, raise, gain, rise, development) |
| additive(noun, extra, supplement, appendage, add-on) |
| adjuvant |
| advancement(noun, change, advance, increase, gain) |
| aggravation(increase, rise, growth, magnification, worsening) |
| aggregation(noun, growth, quantity, pile, gathering) |
| amplify |
| annexe |
| appurtenance(accessory, supplement) |
| attachment(noun, extra, addition, accessory, supplement) |
| bonus(noun, extra, supplement, appendage, add-on) |
| climb(noun, advance, increase, progress, growth) |