'Err' definitions:

Definition of 'err'

verb

To make a mistake or be incorrect [syn: err, mistake, slip]

verb

Wander from a direct course or at random; "The child strayed from the path and her parents lost sight of her"; "don't drift from the set course" [syn: stray, err, drift]

Definition of 'Err'

From: GCIDE

Err \Err\ ([~e]r), v. i. [imp. & p. p. Erred; p. pr. & vb. n. Erring (?; 277, 85).] [F. errer, L. errare; akin to G. irren, OHG. irran, v. t., irr[=o]n, v. i., OS. irrien, Sw. irra, Dan. irre, Goth, a['i]rzjan to lead astray, airzise astray.]
1. To wander; to roam; to stray. [Archaic] "Why wilt thou err from me?" --Keble. [1913 Webster]
What seemeth to you, if there were to a man an hundred sheep and one of them hath erred. --Wyclif (Matt. xviii. 12). [1913 Webster]
2. To deviate from the true course; to miss the thing aimed at. "My jealous aim might err." --Shak. [1913 Webster]
3. To miss intellectual truth; to fall into error; to mistake in judgment or opinion; to be mistaken. [1913 Webster]
The man may err in his judgment of circumstances. --Tillotson. [1913 Webster]
4. To deviate morally from the right way; to go astray, in a figurative sense; to do wrong; to sin. [1913 Webster]
Do they not err that devise evil? --Prov. xiv. 22. [1913 Webster]
5. To offend, as by erring. [1913 Webster]

Synonyms of 'err'

From: Moby Thesaurus

backslide,
be in error,
be mistaken,
be wrong,
blunder,
bungle,
commit sin,
degenerate,
deviate,
divagate,
do amiss,
do wrong,
drift,
excurse,
fall,
fall into error,
foozle,
go adrift,
go amiss,
go astray,
go awry,
go wrong,
goof,
judge amiss,
lapse,
meander,
misappreciate,
misbelieve,
miscalculate,
miscompute,
misconjecture,
misconstrue,
misdeem,
misesteem,
misestimate,
misevaluate,
misinterpret,
misjudge,
misreckon,
miss,
miss the mark,
misthink,
misvalue,
offend,
pererrate,
ramble,
rove,
serve Mammon,
sin,
slip,
slip up,
snake,
straggle,
stray,
stumble,
transgress,
trespass,
trip,
twist,
twist and turn,
wander,
wind