to go or cause to go from a frozen to a liquid state
(often + out) to become less numb or stiff from cold as a result of exposure to warmth
said of the weather: to be warm enough to melt ice and snow
to make or become less hostile
Relations with Iran have thawed
to make or become less aloof, cold, or reserved
(often + out) to cause (something) to thaw
A largess universal, like the sun, his liberal eye doth give to every one, thawing cold fear — Shakespeare
[Old English thawian]