man up

to be brave or to take responsibility for the consequences of your actions

Thankfully, we now live in an era in which discrimination, be it on the basis of race, gender, religion or whatever else, is taken very seriously. In the area of gender equality, our aspirations of political correctness have been reflected in language, so we're now for example obliged to talk about a chairperson (and not a chairman), a salesperson (and not a salesman) or a firefighter (and not a fireman). It seems a bizarre twist, therefore, that in recent years there's been a flurry of creative coinages based precisely on the word man, which as well as combining with other words (often for humorous effect, e.g. mankini, manny), has also had the rare achievement of becoming a new phrasal verb. If you tell someone to man up, you're basically telling them to 'get a grip' and start acting in a brave, responsible way.

we … seem to have come full circle, using a word infused with gender-specific stereotypes in a gender-neutral way

Popular use of man up often occurs in the imperative form, as in for example: Man up and start doing the right thing. In general conversation, its context is usually either instruction (e.g.: She told him to man up) or evaluation (e.g.: Jack really needs to man up and …), and as the second citation above shows, it can be used in reference to both men and women. It therefore bucks the trend of enforced 'gender neutrality' as shown in words like chairperson. Somehow, telling someone to person up just doesn't have the same ring to it, precisely because the meaning of the expression is tied up in the stereotypical qualities of masculinity and everything that the word man implies – being tough or brave in the face of adversity, etc. We therefore seem to have come full circle, using a word infused with gender-specific stereotypes in a gender-neutral way. I wonder if in years to come we'll start using the expression woman up as an exhortation to both genders to exhibit the stereotypical qualities of the 'fairer' sex – being sensitive, caring etc. Somehow, I don't think so …

Background – man up

The phrasal verb man up did exist before the new usage described above, originally functioning as an alternative to the transitive verb man in the sense of 'to provide something with the people needed to operate it' (the verbs staff and staff up would be the more politically correct alternatives commonly used today).

This new sense of man up adopts the particle up on the model of other phrasal verbs often realised as imperatives demanding that people do a particular thing, as in e.g. hurry up, shut up, wake up etc.

The popular new meaning of man up seems to have emerged from the sublanguage of American football, where it originally referred to man-to-man defence, later taking on the more general idea of resilience in the face of adversity. In US English, informal 'macho' alternatives for the same concept are sack up, nut up and even cowboy up (which has its origins in rodeo). With a slightly different nuance, in US usage there's also Yiddish mensch up, which lies somewhere at the intersection of being courageous and having strong moral principles.