Here are some sentences that mean "stiff, unnatural and unskilled" for your reference:
The writing of this paper is stiff and unnatural, and it is difficult to read and understand.
His acting skills are unnatural, and he seems to be working hard in front of the camera and lacks realism.
The language of this translated article is very blunt, and it seems to be directly translated, unnatural and fluent.
The child's dance movements look stiff and unskilled, and there is no sense of fluency and beauty.
His painting skills are very unskilled, and his paintings look stiff and lack artistic sense.
Her oral expression is unnatural, which sounds like a blunt endorsement and makes people feel uncomfortable.
The director of this film is very blunt, and it seems as if he is simply copying the plots of other films, lacking innovation and naturalness.
His style of writing is unnatural, and it looks like he is making up words, lacking a real sense of nature.
The performance of this team is stiff and unskilled, and it seems that there is no tacit understanding and proficiency.
His spoken English is blunt, which sounds unnatural and sometimes even confusing.
Her acting skills are very stiff, and every movement and expression seems to imitate others, lacking natural and true feelings.
The choreography of this song is unnatural, as if it were impromptu, without fluency and beauty.
His typing speed is stiff and unskilled, and he seems to be struggling and not fluent.
His oral expression is very blunt and sounds unnatural, which makes it difficult to understand what he wants to express.
Her dance is very unskilled, looks stiff and lacks beautiful rhythm and beauty.
The scenery design of this performance is very stiff and unnatural, and it looks abrupt and discordant.
His eloquence is blunt and unskilled, and it doesn't sound smooth, like memorizing a manuscript.
Her acting skills are very stiff, and she seems to have no emotional and inner expression and lacks realism.
His spoken English is unnatural, which sounds like machine translation, lacking fluency and naturalness.
Her writing is very unskilled, the structure of the article is stiff, the sentences are not fluent, and it is very difficult to read.