An example of an ambiguous phrase appears in "they stood near a group of alien lovers", which without a hyphen implies that they stood near a group of lovers who were aliens; "they stood near a group of alien-lovers" clarifies that they stood near a group of people who loved aliens, as "alien" can be either an adjective or a noun. On the other hand, in the phrase "a hungry pizza-lover", the hyphen will often be omitted (a hungry pizza lover), as "pizza" cannot be an adjective and the phrase is therefore unambiguous.