Nature
At the beginning of the play, Sir Alexander describes Moll as "a mermaid / Has tolled my son to shipwreck" (1.2). While mermaids are traditionally equated with sirens or other enticing creatures, Sir Alexander instead uses the term "mermaid" to indicate something strange. He precedes this metaphor with the remark that Moll "strays so from her kind / Nature repents she made her" (1.2). In comparing Moll to a mermaid, therefore, Sir Alexander seeks to emphasize Moll's "unnatural" existence as a woman who wears men's clothing.
Monstrosity
Sir Davy Dapper is somehow even more cruel toward Moll than Sir Alexander. While Sir Alexander refers to Moll as a "mermaid" who has lured Sebastian to destruction, Sir Davy does not mince words when he calls Moll "A monster! 'Tis some monster!" (1.2). Here, Sir Davy compares Moll not only to an unnatural creature as Sir Alexander did, but actually to something more sinister and destructive. Once again, the noblemen of the play are dedicated to labeling Moll as something "other."
Windmill
When Sir Davy Dapper decides to teach his son a lesson by having him arrested, he confides in Sir Alexander, saying, "I have in my brain / A windmill going that shall grind to dust / The follies of my son" (3.3). Here, Sir Davy uses a metaphor to compare his secret scheme to a windmill – or strong, unstoppable force – that will solve all of his problems. Notably, however, Sir Davy incorrectly associates the windmill with "grinding" and violence, which reflects his own ignorance and even foreshadows his failed plot against Jack Dapper.
Marriage
When asked when she plans to marry, Moll explains that she is not interested in marriage whatsoever. She says that she enjoys having an entire bed to herself and that she is "man enough" to keep herself supported. Moreover, Moll concludes by saying, "marriage is but a chopping and changing, where a maiden loses one head, and has a worse i'th'place" (2.1). Here, Moll uses the metaphor of the guillotine (a mechanism used for beheadings) to explain that she sees marriage as the destruction of women's autonomy. When a woman "loses one head" (i.e., maidenhead, or virginity), she has a worse one put in its place – meaning that marriage is ultimately detrimental to women's lives.
Social Mobility
In another description of Moll, Laxton says that she "slips from one company to another like a fat eel between a Dutchman's fingers" (2.1). Here, Laxton uses a simile to describe Moll's remarkable social mobility – she can fit in across various social strata, among noblemen and commoners alike. Laxton, however, takes Moll's chameleon-like ability as evidence that she is morally loose, and chooses to pursue her as if she is a prostitute.