Final answer:
Each word in the provided list - cryptic, unsportsmanlike, sheepish, expressionless - functions as an adjective, which modifies a noun or pronoun to provide more detail about it. Examples and explanations for each demonstrate how they serve to describe or modify nouns in sentences.
Step-by-step explanation:
In addressing the question regarding the part of speech for each word in the given list - cryptic, unsportsmanlike, sheepish, and expressionless, we need to analyze the function and form of each word within a sentence.
Cryptic is an adjective because it is used to describe something that is mysterious or unclear. Adjectives modify nouns or pronouns by giving more information about them. An example sentence could be: 'The instructions were cryptic and hard to follow.'
Unsportsmanlike is also an adjective. It describes behavior that is not fair or respectful within a sports context. For instance: 'The player's unsportsmanlike conduct resulted in a penalty.'
The word sheepish is another adjective, often indicating embarrassment or a lack of confidence. Used in a sentence, it could be: 'He gave a sheepish smile after realizing his mistake.'
Finally, expressionless is an adjective that describes the absence of expression, as in 'Her face was expressionless during the performance.'
These words can be identified as adjectives primarily by their capability to provide details about a noun, modifying it to convey more precise information about the character, quantity, or state of the noun they are describing.