Baby blues

postnatal depression

Be in a blue funk

be very, very worried

Blue

drunk

Blue

depressed

Blue

belonging to conservative party

Blue

feminist, intellectual, erudite

Blue

obscene

Blue

Lycaenida, beautiful blue butterfly

Blue

police officer

Blue

woman who hates men

Blue baby

baby afflicted by cyanose

Blue bag

Typical briefcase of legal professionals

Blue bag

Supplement of washing powder

Blue blood

Noble lineage

Blue book

Government report

Blue book

exam book

Blue book

VIP book

Blue book

Periodical guide of bars and brothels

Blue cheese

Strong cheese

Blue chip

high-value chip in gambling

Blue chip

profitable share

Blue dahlia

something that is absolutely impossible

Blue devils

Echium vulgare

Blue devils

state of depression

Blue devils

delirium tremens

Blue ensign

Flag on ships

Blue film

dirty film

Blue fox

Alopex lagopus

Blue girls

Factory girls

Blue gum

Eucalyptus globulus

Blue helmet

United Nations military

Blue jeans

Blue joke

dirty joke

Blue law

strict Puritan law

Blue mould

type of mould: genus Penicillium

Blue notes

Minor third and minor seventh in a major scale

Blue pencil

pencil of the censor

Blue Peter

Flag indicating 5 minutes start of sailing race

Blue pill

pill containing mercury used as a laxative

Blue point

blue oyster

Blue ribbon

ribbon of the Order of the Garter 

Blue ribbon

first prize

Blue ribbon

Symbol of teetotallers

Blue rock

Columba livi

Blue rock thrush

Monticola solitarius

Blue vitriol

crystallized copper sulphate

Blue water

open sea

Blue whale

Sibbaldus musculus

Blue with anger

Very, very angry

Blue with cold

Very, very cold

Bluebeard

hater of women, someone who treats women cruelly, killer of women

Bluebeat

Music style: precursor of reggae

Bluebell

Campanula rotundifolia I confess: a flower I love ...

Bluebell

Scilla non-scriptus

Blueberry

Vaccinium

Bluebird

Sialia

Bluebottle

Calliphora

Bluebottle

Centaurea cyanus

Bluecoat

Police officer

Bluecoat

Unionist (American Civil War)

Bluecoat

Christ's Hospital scholar

Blue-collar worker

Worker in factory / workshop, as opposed to white-collar workers (office workers etc.)

Blue-eyed boy

favourite, darling, crown prince

Blue-eyed soul

soul music made by whites

Bluefish

Pomatomus saltatrix

Bluefish

Salmo trutta

Bluegrass

Poa pratensis

Bluegrass

Country music, especially with 5-string banjo

Blue-headed wagtail

Motacilla flava: such a lovely bird ...

Bluejacket

sailor

Bluenose

person from Nova Scotia

Bluenose

very conservative Puritan

Blueprint

design

Blue-ribbon

first-class

Blues

Music style

Blues

State of depression

Blue-sky

without value, unreliable, overambitious, unrealistic

Blue-sky law

Law for the protection of the stock market

Blue-sky research

Purely scientific research

Bluestocking

Erudite woman (sexist expression)

Bluestocking

Recurvirostra americana: such an elegant bird

Bluestone

Bluestone

crystallized copper sulphate

Bluethroat

Luscinia svecica

Bluetit

Parus caeruleus

Blue-winged teal

Anas discors

Bluey

vagabond's pack

Bluey

conscription note

Have a blue fit

be very, very frightened

Into the blue

into the unknown

Like a blue streak

fast as lightning

Once in a blue moon

hardly ever

Out of the blue

unexpectedly

Put someone in a blue fear

make someone very, very afraid

Run round like a blue-arsed fly

be very, very busy

Shout blue murder

Shout very, very loudly

Talk a blue streak

talk nineteen to the dozen

The Blues

Royal Horse Guards

Wait till you are blue in the face

wait for a very, very long time

Win your blue

be elected as representative student of Cambridge or Oxford University