The novel is set in the 1730s and 1740s and tells the life story (in the first person) of Roderick "Rory" Random, who was born to a Scottish gentleman and a lower-class woman and is thus shunned by his father's family. His mother dies soon after giving birth and his father is driven mad with grief. Random's paternal grandfather coerces a local school master into providing free education for the boy, who becomes popular with his classmates (some of whom he encounters again in subsequent adventures) and learns Latin, French, Italian and ancient Greek. The language accomplishments are despite, rather than because of, the abusive tutor who oppresses Random at every opportunity. Finally Random is cast out after the tutor exacts revenge for one of Random's escapades and denounces him to his grandfather. With none of his paternal family willing to assist him in any way, Random relies on his wits and the occasional support of his maternal uncle, Tom Bowling.
The naive Random then embarks on a series of adventures and misadventures, visiting inter alia: London, Bath, France, the West Indies, West Africa and South America. With little money to support himself, he encounters malice, discrimination and sharpers at every turn. His honest and trustworthy character and medical skills do however win him a few staunch friends.
Roderick spends much of the novel trying to attract the attention of various wealthy women he meets, so that he can live comfortably and take up his rightful entitlement as a gentleman. To that end he poses as a nobleman several times, including once while he is in France.
Roderick and his companion Hugh Strap end up serving twice on British ships, once on a privateer and once on a warship after being press-ganged.
The novel ends happily when Random is reunited with his now wealthy father in Argentina. He inherits some funds immediately, enabling him to marry the lovely Narcissa without the consent of her guardian brother.

Question: What does Random pose as?
Answer: A noblemen
Alternative answer: A nobleman