The phrase "most deep set" refers to something that is firmly embedded or grounded, implying strength, stability, and immovability. Its antonyms include 'shallow', 'superficial', 'surface-level', and 'skin-deep', all of which reflect the opposite qualities. These terms suggest that something or someone is not fully committed, lacks resilience, or has a fleeting presence. 'Shallow' refers to a lack of depth or consideration, while 'superficial' indicates a lack of depth or authenticity. Similarly, 'surface-level' implies that something only exists on the surface and not beyond it, while 'skin-deep' suggests a shallow appearance that lacks material substance.