WordNet sense 1 (capable of being influenced or formed):

plastic

WordNet sense 2 (easily impressed or influenced):

impressible, impressionable

WordNet sense 3 (capable of being shaped or bent or drawn out):

ductile, malleable, pliable, tensile, tractile

WordNet sense 4 (having or given a form or shape):

formed

WordNet sense 5 (able to adjust readily to different conditions):

elastic

WordNet sense 6 (capable of adapting (of becoming or being made suitable) to a particular situation or use):

adaptable

WordNet sense 7 (capable of being bent or flexed or twisted without breaking):

bendable

WordNet sense 8 (able to flex; able to bend easily):

flexible, flexile