Definitions

1. adjective

relating to or having a low or negative tropism, especially in the sense of responding poorly to stimuli or failing to exhibit a clear direction of growth or movement

“The nontropic nature of the plant made it difficult to grow in the garden.”

2. noun

a response or movement that does not follow a tropic or directional tendency, especially in the sense of exhibiting a random or unpredictable orientation

“The nontropic behavior of the particles in the experiment was a major surprise to the scientists.”