Collocations for rapid - adj.

be, seem
become

extremely, fairly, very, etc.
extraordinarily, unusually
relatively
increasingly

Rapid is used with these nouns:
acceleration, access, accumulation, advance, ascent, assessment, breathing, build-up, burst, change, climb, completion, decay, decline, decrease, demise, depletion, deployment, descent, destruction, deterioration, development, disappearance, disintegration, drop, emergence, erosion, escalation, establishment, evolution, exit, expansion, fall, fire, fluctuation, footstep, gain, growth, heartbeat, identification, improvement, increase, influx, integration, loss, motion, move, movement, onset, pace, passage, progress, progression, promotion, pulse, rate, recovery, reduction, reform, repair, resolution, response, retreat, return, review, rise, shift, spin, spread, stride, subsidence, succession, transformation, transit, transition, turnover, withdrawal