Difference between Glad and Lief

GLAD vs LIEF: NOUN

Any of numerous plants of the genus Gladiolus native chiefly to tropical and South Africa having sword-shaped leaves and one-sided spikes of brightly colored funnel-shaped flowers; widely cultivated
Gladness.
A gladiolus.

Very willing; pleased.
Providing joy and pleasure.
Appreciative.
Experiencing or exhibiting joy and pleasure.
Cheerful and bright
Feeling happy appreciation
Showing or causing joy and pleasure; especially made happy
Glad of it.
Pleased; joyous; happy; cheerful; gratified; -- opposed to sorry, sorrowful, or unhappy; -- said of persons, and often followed by of, at, that, or by the infinitive, and sometimes by with, introducing the cause or reason.
Eagerly disposed to act or to be of service
Pleased, happy, satisfied
(`lief' is archaic) very willing
Wearing a gay or bright appearance; expressing or exciting joy; producing gladness; exhilarating.

Readily; willingly.
In a willing manner
Gladly; willingly; freely; -- now used only in the phrases, had as lief, and would as lief.

Gladsome, cheering, exhilarating, animating. See gladness.
Synonyms Joyous, delighted, animated, exhilarated.
Causing joy or pleasure; giving satisfaction; pleasing.
Feeling joy, pleasure, or satisfaction, especially with reference to some particular event; pleased; gratified; well contented; joyful: rarely used attributively in this sense, but usually in the predicate, where it is used absolutely or followed by of or at, or by an infinitive with to: as, to be glad of an opportunity to oblige a friend.
Widely cultivated
Especially made happy
Shining; bright; cheerful; wearing the appearance of joy: as, a glad countenance.
In good condition; thriving.
Acting smoothly or freely; moving easily: as, a glad door or bolt.
Smooth; level; open. Compare glade.
To be glad; rejoice.
To make glad; gladden.
(transitive; intransitive verb) To gladden.

Elated, Overjoyed, Gratified, Excited, Delighted, Proud, Gladsome, Lief, Cheerful, Beaming, Willing, Pleased, Grateful, Thankful, Happy

Margaret, Catherine, Gemma, Samuel, Liefsome, Jud, Dion, Vive, Liam, Klein, Willingly, Readily, Willing, Glad, Gladly

Fortunate, Elated, Overjoyed, Gratified, Excited, Delighted, Proud, Gladsome, Cheerful, Beaming, Willing, Pleased, Grateful, Thankful, Happy

Christopher, Margaret, Catherine, Gemma, Samuel, Liefsome, Jud, Vive, Liam, Klein, Willingly, Readily, Willing, Glad, Gladly