1. emphasize something
Professional
Social
underline the importance/significance of someone/something
To 'underline' means to draw a line under a word especially in order to highlight its importance. To 'underline' something can also mean to emphasise it. You will often hear expressions such as 'I can't underline the seriousness of this' or 'I can't underline this point enough'. This is a popular expression used often in professional contexts. Similar in meaning to 'stress this' 'to highlight' or 'to emphasise'.
2. draw a line under a word or sentence to highlight or emphasize it
Professional
Social
the key points were underlined in red
To 'underline' means to draw a line under a word especially in order to highlight its importance. Similar in meaning to 'stress this' 'to highlight' or 'to emphasise'.