I've learned all thumbs means physically awkward, especially with respect to the hands.
Is there any word or phrase to describe it in mentally?
The opposite of smooth talker or handling other people well.
I've learned all thumbs means physically awkward, especially with respect to the hands.
Is there any word or phrase to describe it in mentally?
The opposite of smooth talker or handling other people well.
Regarding the ability to handle people well, I would perhaps use the expression people skills. Example: "He lacks people skills".
people skills: the ability to deal with people well (Longman)
Regarding the opposite of smooth talker, I suggest the expression tongue-tied. Example: Why was she always so tongue-tied with this man?
tongue-tied: unable to express yourself clearly or fluently (Princeton WordNet)
You could say, they are conversationally/socially inept.
inept: lacking skill or ability: showing a lack of skill or ability : not done well