From The Collaborative International Dictionary of English v.0.48:
Overblow \O`ver*blow"\, v. i.
1. To blow over, or be subdued. [R.] --Spenser.
[1913 Webster]
2. (Mus.) To force so much wind into a pipe that it produces
an overtone, or a note higher than the natural note; thus,
the upper octaves of a flute are produced by overblowing.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48:
Overblow \O`ver*blow"\, v. t.
1. To blow away; to dissipate by wind, or as by wind.
[1913 Webster]
When this cloud of sorrow's overblown. --Waller.
[1913 Webster]
2. To ascribe an unwarranted importance to.
[PJC]
3. (Music) To blow into (a wind instrument) too strongly, so
as to produce predominantly overtones.
[PJC]