Line by eye refers to a method of drawing or creating a straight line without the use of tools or measurements. Some synonyms for line by eye include freehand, hand-drawn, improvised, ad-lib, off-the-cuff, unplanned, spur-of-the-moment, and impromptu. These terms express the idea of creating something spontaneously, without the aid of pre-planning or specialized tools. While line by eye may seem imprecise, it can also be seen as a skill, where the artist or creator relies on their own abilities and intuition rather than following strict guidelines. Whether it's sketching a drawing or cutting a piece of fabric, line by eye techniques can result in unique and personal creations.