Definition of looks rare
When someone uses the term ‘looks rare’ when talking about an NFT, it is a reference to the attributes that are present in the NFT. The attributes can determine the value of an NFT because some attributes are very uncommon or rare. The more rare an attribute is, the more unique it is and therefore often the NFT containing it is more valuable.
The term can also be used in an ironic way, in this case it actually means that the NFT does not have any rare attributes and could therefore not be very valuable.