The term 'shrewdly tricky' can be summed up with the word 'SLY', which is a three-letter word. SLY is defined as having or showing a clever and calculating nature, especially with regards to one's own interests. It is often used to describe someone who is able to outwit others in order to get what they want. This term is often used to describe someone who is cunning and manipulative, but also has a certain charm that allows them to get away with their schemes.