The term 'Gain Intensity' can be summarized by the word 'DEEPEN, ' which is a six-letter word. Deepening something implies that it is becoming more intense, or that its intensity is increasing. This could refer to anything from a feeling or emotion to a physical action or process. For example, deepening a conversation could mean that the conversation is becoming more meaningful and intense, while deepening a color could mean that the color is becoming more vibrant and intense.