The term 'make ineffective' can be expressed in a variety of ways. The six-letter word 'NEGATE' means to deny or oppose, while the nine-letter word 'HAMSTRING' means to limit or restrict. The seven-letter word 'NULLIFY' means to make something invalid or void, and the seven-letter word 'VITIATE' means to weaken or corrupt. Finally, the ten-letter word 'DEACTIVATE' means to render something inactive or inoperative. All of these words describe the same concept of making something ineffective.