Infix, v. t. [imp. & p. p. Infixed; p. pr. & vb. n. Infixing.] — Webster enters it under “infix”
Etymology: [L. infixus, p.p of infigere to infix; pref. in- in + figere to fix: cf. F. infixer. See Fix.]
1. To set; to fasten or fix by piercing or thrusting in; as, to infix a sting, spear, or dart. Shak. The fatal dart a ready passage found, And deep within her heart infixed the wound. Dryden.
2. To implant or fix; to instill; to inculcate, as principles, thoughts, or instructions; as, to infix good principles in the mind, or ideas in the memory.
1 other Webster entry under this spelling
Infix, n.
Something infixed. [R.] Welsford.
Shades of meaning
Fernald has no entry of its own for infixed; he lists it under inherent.
He lists it without comment; the entries above explain its neighbors.